Complaint about bad signal

My parents live on a small holding about 30 km outside Potchefstroom, NW. Since 2008 we contacted Vodacom and asked them to help us with signal. We even offered some land where they could put up another tower, and they said after 2 years it would be up. It has now been 7 years... In 2014 we communicated via e-mails and they sent out a person who tested the signal and said it was very bad. He said they would pass the info to the engineers department. We have heard nothing since. My parents are two retired people, and we are vey concerned that they would not be able to contact anybody for help should they need it. Especially since the ******s on small holdings in NW has drastically increased. There are other people too that will benefit from better reception. Please help us as we do not want to change our supplier, we have been Vodacom customers since the start of cell phones in SA.