vodacom CANNOT ALLOCATE A PAYMENT

I paid for my cellphone account in time but Vodacom kept calling and sending SMSes to say they need payment on my account. I called them back to try and sort this out and the one consultant asked me to send the proof of payment to ********** but they still continued to harass me wit calls and SMSes, I called again and the consultant this time said I should send the proof of payment to her supervisor which I did but still continued to get calls so I called again the next day and another consultant said they are probably not receiving my POP because I must have send it as a picture not as PDF. So resend the proof as PDF but no one cared to even respond nor did the calls and SMSes stop coming through. I called again yesterday and I was tossed from one consultant to another and from one supervisor to another. Eventually they send me an email to say they have escalated by query to someone to get them to allocate my payment and they promised they would stop the collections people from calling or texting me. But guess what, 8 o'clock this morning I got a call from Vodacom requesting payment. I mean how difficult is it to allocate a payment ?????