Bad service

Im so annoyes by MTN and their bad service of not responding on time to my emails and yet they forever sending me smses to pay an amount of R325 I dont unserstand what I am payin this amount for when already they debited my money twice when my contract already expires in May.<br> <br> They tell me they have convertes my number to prepaid what am I paying another R325 for when they already ripped me off of 623 for two months I am tired of running after this service provider I dnt have time to be following up this aort it oit MTN