Bad and poor services -unauthorized attempt to take money from a client's account

Rain keeps on attempting to take money from my account even though i have complained about their poor service and the network that goes dead every evening when it is needed most. I have since cancelled or terminated the month to month contract but today they attempted to take money from my account when they have through their chat platform confirmed that there is a cancellation. Their continuation to attempt getting money from my account is costing me unnecessary bank charges. Unfortunately they are the worst ISP i have ever dealt with, they have completely failed to identify the problem that causes the network to go off every time after 17:00