Yes, but if your customers have a lot of valuable data in your service, cancelling would make them loose that data. You can technically use this to extort money

Yes, but if your customers have a lot of valuable data in your service, cancelling would make them loose that data. You can technically use this to extort money from your users. Not a viable business plan in the long run, for sure, but there are plenty of businesses that would try, I think.