## Summary On July 29, 2026, my Claude Pro account was upgraded to the Max plan without my authorization, resulting in a charge of ₩327,385 (Invoice #W47FAZS1-0002). I did not initiate this change. ## Account Info - Account email: ekwkqk12@naver.com - Country: South Korea - Support Conversation ID: 215475283552687 ## Timeline - July 19, 2026: Normal Pro plan charge of ₩35,000 - July 29, 2026: Unauthorized upgrade to Max plan — Invoice #W47FAZS1-0002 (₩318,182 + VAT ₩29,762 = ₩327,385) - Jul

[Billing Bug] Unauthorized Pro→Max upgrade

Status Open

Maintainer reply None cached

Activity 4 comments · opened Jul 30, 2026

Summary

On July 29, 2026, my Claude Pro account was upgraded to the Max plan without my authorization, resulting in a charge of ₩327,385 (Invoice #W47FAZS1-0002). I did not initiate this change.

Account Info

Account email: ekwkqk12@naver.com
Country: South Korea
Support Conversation ID: 215475283552687

Timeline

July 19, 2026: Normal Pro plan charge of ₩35,000
July 29, 2026: Unauthorized upgrade to Max plan — Invoice #W47FAZS1-0002 (₩318,182 + VAT ₩29,762 = ₩327,385)
July 30, ~9:00 AM KST: First login of the day — usage meter was already at 30–50% and climbing, despite no prior activity from me that day
July 30, 2026: Changed Naver account password (login email), cleared all related browser data, uninstalled Claude desktop app, blocked international card payments, scheduled downgrade to Pro, contacted support via Intercom

Issue Details

I did NOT initiate the Max plan upgrade
Usage credits have never been enabled on my account (still OFF now)
On July 30 at approximately 9:00 AM KST, I logged in for the first time that day and found usage was already at 30–50% and continuing to increase — indicating that someone or something else was consuming my account's quota
Despite taking all the above measures, token usage continued to increase
There is no self-service option in the UI to remove the payment method or freeze the account

Requests

Please investigate the access logs (IP, client, timestamps) for July 29–30 to determine whether this was caused by unauthorized third-party access or an internal billing system error
Full refund of Invoice #W47FAZS1-0002 (₩327,385)
Reverse the unauthorized Pro→Max upgrade
Since there is no self-service option to remove the payment method or freeze the account, please process this server-side to prevent further unauthorized charges

Related Issues

Several other users have reported a very similar pattern of unauthorized Pro→Max upgrades:

#72336 (Slovakia, June 29)
#64814 (unauthorized Max upgrade, card removal impossible)
#78577 (repeated unauthorized Pro→Max, July 16)
#73773 (repeated unauthorized Max upgrade and charge)
#68429 (unauthorized upgrade led to account deletion)

I would appreciate if you could confirm whether my case is related to the billing error reported on July 12, 2026. Any guidance on protecting my account going forward would also be helpful.

Thank you for your time and assistance.

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4 Comments

MohammadAboulEla · 26 days ago

same happen to me today

tomklamer · 22 days ago

I’m experiencing a very similar issue, including unexplained model usage.

My Claude account has been upgraded to Max 20x three separate times without me intentionally upgrading it.

During an earlier incident, Anthropic Support investigated my account and explicitly confirmed that there were two active subscriptions at the same time for the same organization, causing duplicate/unexpected charges. The subscription issue was corrected/refunded and I was returned to Pro, but Max 20x was subsequently activated again without any action from me.

I have also observed unexplained model usage during periods when I was not using Claude.

So in my case there appear to be two related issues:

Max 20x was activated without my authorization on three separate occasions.
Model usage occurred that I cannot account for.

I don’t want to assume whether this is session/account hijacking or an internal subscription/billing issue. However, because both unauthorized subscription changes and unexplained usage occurred, I believe Anthropic needs to investigate the underlying access logs.

Support previously told me that my case would be escalated to specialists for further investigation, but I have not received any further findings or explanation so far.

It would be extremely helpful if Anthropic could determine:

whether each Max 20x upgrade was triggered by an authenticated customer/session request or internally by the billing/subscription system;
whether the unexplained model usage originated from the same session/client/IP that initiated any of the Max upgrades;
the timestamps and subscription IDs associated with all three Max 20x activations;
whether any of the subscriptions were reactivated internally rather than newly created by a customer action.

This seems very similar to the behavior described in this issue.

I can provide invoice IDs, exact timestamps, screenshots, and my previous Anthropic Support correspondence privately if needed. I’m intentionally not posting account identifiers, billing details, or session information publicly.

dabeku · 17 days ago

Same happened to me yesterday.

Soffy91 · 12 days ago

Same happened to me!