Hey,
first of all, we didn't charge you unethically. It was because you have enabled auto-recharge if your credit balance goes below a certain threshold, and then it will charge your wallet with $10 of credit. Somebody tried to use your service, which let into like charging your wallet again and again, and you have been charged some amount out of goodwill. We have returned the amount to your original source.
Before we conclude this email, I'll mention this again: this was not because of VAPI. It was because you have enabled the auto-reload, and someone has used your account.
So, who is this someone? You need to trace down.