VODACOM - where is your service delivery??

I have been struggling to get an upgrade done for months now. On the first round, the upgrades consultant gave me an incorrect quotation - that was late last year. After I have been waiting for several days I had to find out - by phoning numerous times, that he made a mistake. When I tried to upgrade after that, an incorrect upgrade offer was sitting on their system, which prevented the process to continue. Once again I had to phone them to resolve this and had to wait a certain time for this to be done. So I gave up and left it. Early February another upgrade consultant phoned me making me a great offer. After waiting for several days - I had to phone them again, only to find out it was delivered to the wrong address. That was after he took down my physical address manually... It took RAM more than two weeks to book the incorrect delivery back again. In all this time Vodacom did not keep me updated, I HAD TO PHONE THEM NUMEROUS TIMES. So I decided I am going to cancel my contract of more than 15 years because I cannot have this absolute pathetic service any longer. I was advised that I have to cancel the upgrade first - BUT THEY will let me know when it is done. Of Course That did not happen. I had to phone them again to find out if it has been cancelled. I decided in the meantime that I want to port my number to Cell C - the Vodacom online chat consultant just answered me that I have to contact Cell C. Well according to Cell C I have to change my contract to prepaid first before porting is possible. ONCE AGAIN something that Vodacom could have told me? So now I sit between a rock and a hard place, because I have absolutely no confidence in Vodacom anymore. Will this process be another ****** up, taking weeks and months to be finalised or will I sit with no communication or data because they seemed to have lost the ability to assist people correctly? Any advice????