Vodacom - disappointment

I'm very disappointed in the service I have been receiving from Vodacom! I upgraded my phone in October last year online , they delivered the phone to my home and then a month later started billing me for 2 cellphone contracts , I contacted the call centre and they told me there was a mistake they didn't upgrade my phone but added a new line for me instead with a new number , I've been trying for 3 months to get this sorted out and removed off my name as I did not want a second line but an upgrade on my current line. Every time I call I get told I will be called back , I've been sending them Facebook messages for 3 months following up daily, they finally collected the phone to return but I am still being billed for the number , I want this off my name and refunded all the money as it was your mistake not mine! How can it be so complicated to fix and sort out?