Account in arrears but never missed a payment

I have a contract with the company and it's 7 months now with my line (network connection) going on and off and nobody calls me I have to call so that they can tell me about my account being In arrears and bare in mind that I never missed a payment from since 2019 the contract started. I sent them proof of payments a thousand of them but still and they ruined my credit record now I can't apply for loans for tertiary fees.