My service has been suspended

I am very disappointed with the service I received from Telkom mobile, my simcard has been soft locked not because of my doing, but theirs. I have 4 months left on my contract, and would therefore like to cancel my contract with them immediately. Especially after being told that my service will be reinstated after 3 working days. (which will be on Tuesday 29 September 2015, today only being the 24 September 2015