Poor service

I won a spin the reward upgrade in Feb and since then I have been having issues with my billing, the call centre has been useless in helping me resolve the issue. Last month my account started showing that it was overdue which I don’t understand how if the debit order goes off successfully monthly. I sent my complaint last week and received a reply with the ref:INC-664480 and ref ***1 I was told that my query was going to be referred to the rewards department for the charges to be rectified, but today I receive an sms stating that my account is overdue therefore my services has been disconnected. The call centre can’t even assist me, I’ve been waiting for the team leader to call me back since this morning