Cant even cancel a contract ?!

My contract expired on the 7th of December and I thought like ANY OTHER phone company I could call and cancel it but to my suprise it is not that easy at all. I had to fill in a form and email it throught giving me a 30 day notice of cancelation, meaning the 24 months contract I signed up for now is a 25 month contract. I sent the cancelation letter through on the 8th and went to the store on the 21st to make sure it was cancelled when the manager of the mokopane Mall Telkom told me the letter was never sent through. I HAD TO SEND IT TO HER AGAIN. SO AM I NOW GOING TO HAVE TO KEEP PAYING FOR A PHONE I ASKED TO CANCEL JUST BECAUSE OF TELKOMS BAD ADMIN WORK?? IM AM VERY UPSET WITH THE POOR SERVICE FROM TELKOM AND WILL NEVER BE TAKING OUT ANOTHER CONTRACT AGAIN IF I EVEN EVER GET THIS ONE CANCELLED !!