Phones dropping calls for 4 months

Our phones have been dropping calls for the past four months. After numerous followups and passing the buck, one of Neotel's subcontractors eventually installed an antenna on top of our office block on the 1st March 2016 - we were told this would fix the problem. <br> <br> The problem persists, sometimes our phone calls last only a few seconds, other times 5 minutes, before getting cut off. We have tried phoning and emailing Neotel, but there has been no response.<br> <br> Neotel, please provide us with the service that we are paying you for.