Poor service from Vodacom

I upgrade my contract last year November 2018. I inserted a simcard into the new phone. I could not make phonecalls. Vodacom advised me to cancel the contract and take out a new contract and then do a simswab. I did that. They collected the phone. After a waiting period I took out a new contract. Everything seemed fine but then I discovered they never canceled the first contract and has been charging me for two new phones and contracts. I only have 1 new phone. I also have been staying near Cresta and basically have no reception for any calls. I run my own business from home and have a lot of trouble with the network reception. After reporting it numerous times over a period of 10 years, they still have done nothing about it. They tell me their is a third party involved and they must install a new cellphone tower. Is that not ridiculous! I stay in the middle of Johannesburg, have 3 contracts with Vodacom and they can't improve the network signal. I reported it to a friend that works for a cellphone company installing towers. He drove to the nearest tower and said his phone had no signal right under the tower. I am also on a neighbor whatsupp group. Other neighbour's are also having the same bad signal problem. I have been a client of Vodacom for the past 20 years and would like to receive better service for my loyal support.