Unifi suck

We had an oustanding amount of R780 which we paid using ozow. I sent them the proof of payment. According to me this account had been paid in full. Every month I get these emails stating I owe them R70 and now it is R230. Pls I can not help that the call centre agents could not open a screen shot. I HAVE PAID THIS ACCOUNT IN FULL. STOP SENDING ME TREATENING MAILS!!!!!!!!