Wireless Service Connectivity Failing - Signal Not Good Enough

I have 2 landlines which Telkom wants to upgrade to a wireless service. The signal is not good enough to support a wireless device. These two landlines are for business and very important and I can't upgrade them.

I have a Telkom representative calling me every week asking if they can deliver the wireless phones and I explain to them the poor signal situation and they say a technician will be dispatched to sort the issue.

This has been happening since January and I have still not had a technician contact me. Each time someone calls I explain everything but I never hear back from a technician.

I am not sure who to call or ask, in order to resolve this issue. I have had more than 10 calls from Telkom all promising to resolve the issue but I have heard nothing back from them.