bad service

I am trying to fix my adsl account 14:October 2015. I have adsl contract. Added uncap. Now I tried to cancel uncap and keep the 10 megabyte line with 50 gig and uncap evenings. Now i'm told they can not remove the uncap and leave my 50gig and 10 megabyte line. I phoned more then 5 times. During my calls, they said, that they need to check something, after a minute the phone just goes silent. I just phone them again (time is now 12:40) she just put the phone down in my ear. What I need to know now what it will cost me to cancel my contract with telkom.... i'm paying R1500 for this service. Do have a ref number for 14october2015 call but what good is it. they can not or will not help......