When I tried out the AWS free trial thing, they had some issue where EC2 instances would become totally unreachable within minutes of being created. Support ask

When I tried out the AWS free trial thing, they had some issue where EC2 instances would become totally unreachable within minutes of being created. Support asked me to leave some bugged instances running so they could investigate. Then I was billed for these instances. I asked for a refund, but Amazon says they have no record of the charges, even though I can see them in my Amazon account. Great.