DSTV Wont let me cancel my service!

I have been unable to cancel my service for the last month! Each time i contact them I am either disconnected while getting put through to the correct department or am informed that there are issues with there system??. This has been going on for the last 30 days. I have since blocked there debit,seeing as it is impossible to cancel with them. I have been a loyal client of yours for many years and this is how they force me to act. Disgusting practice.