How do I know about my other accounts?

Hello,
A week ago I got the next message:
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Hi,

we noticed that you created more than one account at PBXes.
That is welcome but also creates considerable load on our servers.
Better would be to stay under a single account as written in our
Terms of Service.

You can delete (in Personal Data) or upgrade the additional account

2042263

to paid within a week. Otherwise we are going to disable it.

It is neccessary to delete/upgrade exactly the above mentioned account,
not any other in its place.

Thanks for your cooperation.

Best regards,
i-p-tel
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In fact, I created two accounts (qweasdaqwe, testtest11) for testing purposes. After I did my choice, I deleted those accounts and registered the new 2042263.

The message you sent me, you wrote that I have more than one account.
How do I know about my other accounts? Could you told me about those accounts you mentioned in the message?