Loss of revenue due to no service

We suffered loss of revenue in April 2017 when we ran a marketing campaing however our Telkom line was down for a very long time and not working during the same period. We reported the matter and your technical team did not fix and attend to the matter for weeks as a result we lost out on the potential revenue and cost of the campaign. We are currently sitting with the unpaid invoices from that same time frame. Please advise who is the relevant person to forward all the information and handle this case? We will be claiming back these charges from Telkom as you were not able to service us and we lost business