MTN NOT 'HONORING' NASHUA UPGRADES

I was a Nashua Mobile customer who was migrated to MTN when Nashua 'sold out' - I always received my upgrade in May with Nashua Mobile - even now after it was migrated to MTN, MTN themselves sent me a notification that my upgrade was available on 01/05/15.<br> So I go in to do my upgrade - only to be told I must pay an extra R180 a month for the next 4 months as MTN didn't take over the hardware costs from Nashua - or I can wait till my Nashua contract expires and take one out with MTN - IF NASHUA CUSTOMERS WERE MOVED TO MTN, AND I'VE BEEN PAYING MTN FOR THE LAST HOWEVER MANY MONTHS, SURELY MY CONTRACT IS NOW WITH MTN ALREADY? SURELY THEY 'BOUGHT' MY CONTRACT? DIFFERENT STORES GIVE DIFFERENT STORIES, ONE OF THEM SAYING I NEED TO GET HOLD OF RETENTIONS ON 808????? GOOD LUCK WITH THAT, I'VE TRIED, DIFFERENT TIMES, ON DIFFERENT DAYS AND ALWAYS CANNOT GET THROUGH - AND OBVIOUSLY NO ONE REPLIES TO EMAILS. I SUPPOSE I WILL GET CELL C TO BUY OUT MY CONTRACT ON THEIR NEW OFFER AND LEAVE MTN. SURELY A COMPANY (ANY COMPANY) HAS A MAIN GOAL OF INCREASING THEIR CUSTOMER BASE - NOT LOSING CUSTOMERS?