Definitely comunicate with Google using their contact form. And create a new gmail account to use to login to your account and take the old login out. This definitely looks like somebody got access to your gmail address.

I never saw something like this before, but I'd expect that if you explain the situation, Google may give you a refund. They probably won't give you your money back, but will credit your account with that same amount.

Also I'd go to the police and report this.

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