Poor SERVICE

I took a phone with contract then Jan I changed the bank so i tried to reach them on WhatsApp to arrange payment method no avail then my phone was switched off by them, next I check my emails I got a banking details that states where should I make payment I did just that pay at fnb then send proof of payment by WhatsApp, it was month end Jan so I expected to get all the benefit I paid for no data no airtime till today poor service, when I call they say their still busy with my enquirie for how? Now I will have to pay again next week