Where are the arrears coming from when i have been paying monthly?

I only started using Rain this yr. Their network works but its slow. I have had a problem with them suspending my line without any warning or explanation. This month alone they suspended my line twice. First time they said i have arrears but i have just paid them on the 30/04 and they said i should commit that i will pay the amount by the 26/05 which i did but i asked how am i in arrears when i have been using and paying each month? Since they suspended me, no one has bee in contact with me, however I have left them numerous emails which they dont reply to. Now i feel conned because when i have an option of paying using my app which is what i have been doing ever since. When i check their statements there are " unsuccessful bills " but when i check my bank statements the payments appears. What i have done is, i sent to rain my 3 months bank statements to prove that I have paid and not one person have contacted me. They are not even saying that they maybe wanna terminate our deal or something. I paid but they are just making me suffer and i dont know why.