How many times does amazon.com send out a policy warning before eventually closing down a sellers account?

Answer 1

One warning depending on offence and length of offence, for example fraud is an instant close down and the ISP address of the offending account will be passed on to law enforcments. Amazon.co.uk (com) have the right to pass on detail to the police as needed.

However simple offences i.e late payback, failing to send gift may require warnings however will not remotely restrict your account. Expect negative seller feedback however.

I hope this helps.