BAD SERVICE FROM MTN WHILE IS MY FIRST MONTH

i have recently made a month to month router from MTN and i paid an amount of R529.00 which they told me its for the upfront paymnet and pro rata , now MTN sent me a statement saying that i am owing R606.00 Back back emails were sent regarding this and they keep on opening tickets , now my survices has been suspended when i go to the brunch they say thy cant see my payment , this is a bad service from MTN since its my first month with MTN i have sent my bank statement and POP numrious times but they still cant help me . your services are heartbreaking since i have paid this . my numbers are ***.