NO FEEDBACK BUT GOT LETTER OF DEMAND!!!!!

I HAD UPGRADED MY CONTRACT BUT THE UPGRADE WAS NEVER DONE! GETTING BILLS FOR CALLS WHEN I STILL HAVE FREE MINUTES!!! THE ISSUES I AM HAVING WITH YOU PEOPLE ARE ENDLESS AND NOBODY WANTS TO HELP. I HAVE BEEN TO THE STORE MANY TIMES, CALLED AND EMAILED TO DATE WITH NO RESPONSE BUT NOW GET A LETTER OF DEMAND!!! YOUR SERVICE SUCKS & I WANT TO DEAL WITH VODACOM DIRECTLY