Complain and they can cancelation of the the service

I have tried so much to reach out to them regarding my account, regardless of my efforts they keep silent and they don't care even to fix the problem. Last month of November we agreed that I stop paying the account on the 25th and start to pay on 1st and after making the payment I should send them a message so they can do ammendment on their site. I did send a message but they didn't help instead they now shifted the date and say they will do promise to pay until 25th after payment they will change. But this promise to pay doesn't work because as we speak I don't have internet connection, since I last month I have been going through interrupted internet connection, they said I am in arrears but I am not, I even sent them one year proof of payments but they over look that. I don't need to use 5G rain network anymore, is the same as not having internet but I am paying every month. I want to let them know that they can cancel the subscription. I am enough