Bad service

To start. I have a 4mb line with with Telkom and only get 2mb download speeds and on some days if I am lucky get 2.3mb download speed and .3 upload. Keep in mind that I am paying for 4mb and don't get the service for 4mb I do however get a lot of up and download errors. I pay my bill every month and when my contract ended I was not contacted by Telkom to find out if I want to continue with the service on a discounted rate or anything of sort. They just continued with the service and i was billed with almost R900 instead of the R650 I normally paid. I actually had to call them for the discount rate. Now my account is in in arrears. I recently decided that I'm gonna try their LTE packages which is covered in my area. I app**** for this service last week Friday and got a call back on 18/12/2015. During the telephonic application the call got cut and the person never called back to finalize the application. I spend the half of Saturday (19/12/2015) to find someone to tell me what is going on,even went to one of the shops and was told that this application can only be done online or call 10213.I finally got someone and was told that the application was declined because i still owe them?