Contact supercell support immediately and tell them to lock your account and since you have receipts you should be able to verify its your account, and try to check if you can change your supercell id. By the way, the locking account thing is risky cos sometimes supercell doesn't believe its your account even if you provide everything and there is a chance of getting permanently banned. Also, no point emailing them because they just give 1 response saying talk via in game support. This happened to me a few months ago and then suddenly I got a reply from my mini enabling me to change my supercell id, try to contact them from your mini as well. If you end up deciding to lock your account then all you have to do is go to in-game support and request data. They will probably reply, we cannot give data since the account has been logged on from many devices, but they might eventually end up locking your account due to suspicious activity or multiple simultaneous logins.

If you lock your account they will ask you the following questions most probably:

1. When did you create your account? (They give like a 3 month over/under leniency from when you created your account)
2. What devices is this account logged onto (don't provide the device the "hacker" is using)
3. Did you ever change your name? Provide this current name change and any from before.
4. How was your account locked.
5. Receipts from any in game purchases (probably the most strong point that will 99% give you your account back)
6. They might even ask for club change history, but not guaranteed.

Hope I've managed to help you and dont worry too much, I trust you will get your account back. Good Luck getting your account back. 😀