What would you do if you got a complaint about a user your hosting for sending out spam?
Would you:
1. suspend their account and check if the spam did come from them
2. not take any action
3. suspend their account, send a notice that it will be deleted and tell them to get their files
4. delete their account and files/data
Would you issue a refund for a paying customer if they requested it? Would you be worried about them doing a chargeback if you dont give them a refund?
I'd suspend their account, investigate the issue and then decide on what to do depending on what I found from the investigation.
If I found in fact that they were guilty, I'd contact them regarding the matter and discuss their options. If they continued, I'd terminate their account and may even send them an invoice violation of the Terms of Service & Acceptability Use Policy. In my Terms of Service it actually states that the client may be invoiced for up to $500 per spam e-mail sent; I've thankfully never had a problem so far... but you never know what the future may hold.
I would by no means offer them a refund. It also clearly states in my Terms of Service and Acceptability Use Policy that no refund will be given, regardless of the reason for the refund demand. Meaning I'd be under no obligation to refund the client, and due to the fact that they actually violated the TOS and AUP, I wouldn't refund them.
I wouldn't be worried about a charge back either. The bank I bank with is extremely good, it's Barclays PLC. In the past I've had a few problems, however I've always "won" as it were. I think choosing the right bank is very important when starting up a business; I've always had my personal accounts at Barclays, yet when I started I decided to have my business account over at Lloyds TSB - Had an awful time, and quickly moved it over to Barclays PLC. Don't really know why I chose to use Lloyds TSB, yet am now very happy that I've everything at Barclays. (Actually, had I still been with Lloyds TSB I would be worried about a charge back as when the business account was with them, there was a problem - and they weren't interested in hearing my side of the story. So I quickly moved the business account over to Barclays PLC, and have had no problems at all)