****** and continuously abused!!

Total harassment! After logging a complaint on Hello Peter, I was promised an investigation into my matter, lo and behold, I got another notification that I didn't pay my premium for the last month before the deactivation of my membership. This is what happened: I cancelled my membership with Momentum on the 21st of March to which they notified that I am liable to a 30 day notice period. Sensible right? Well, on the 1st of April they tried to debit my account and found no money, which I was aware of and paid manually. I then paid the premium after the 16th of April, which naturally meant that that was the last debit of the scheme. Right? Well, according to Momentum, no. They tried to debit again on the 1st of May when the membership had already been cancelled, which I questioned why and they said I didn't pay my last premium. Which isn't true by the way, because I have a screenshot proof of payment that I sent to the person who responded to my initial complaint on Hello Peter. He promised to investigate and get back to me only to disappear and I get an email again to say I owe Momentum and that my membership is suspended. How do you suspend a cancelled membership? Further more, what happened to the proof of payment that I sent? I could even get a bank statement to prove this but nooo, Momentum wants to just chow another premium of something I cancelled. Please advise and take this matter to the Ombudsman because I'm not prepared to pay that premium twice from a student budget. Infant, I will not pay it because I've already done so. This company has a high level of thievery, *****ed was and total abuse of customers. I will never ever recommend their services to another student. They are just well presented ******!!!!