Rain has poor internet speeds, support and won’t cancel my subscription

I joined Rain in early March 2022, but was plagued with the line constantly dropping and poor internet speeds. The support was so slow to attend to my support tickets so I decided to cancel my service by the end of the month. I used their cancellation process on their web platform and also told the customer service agent once they had finally got back to me about the speeds that I had cancelled. I was told that Rain would contact me to arrange collection of the router. To date I have not received a call or any correspondence to arrange collection. My account was debited for the service again in April and May even though I had cancelled. I emailed Rain support on the 1st of May to enquire and resolve the issue, but my correspondence to them has been ignored. I have yet again emailed customer support on the 1st of June having being billed again. I am at my wits end have no other option but to resolve the dispute via the ombudsman.