Refusal to commit to problem

A flat of mine was done by Witbank Pest control for ****roaches on 13 April 2018. A week later I phoned to report that the problem persist. Their reply was to do a follow up and house was done on 17 April 2018. The tenant reported back to me on 30 April saying the roaches are still there. I phoned on 2 May 2018 Pest control and spoke to the manager who was quick to say that everyone else is happy with result except me. They said will send someone to investigate the problem but only a worker with another batch arrived and sprayed the flat with me and the tenant present at the flat. 12 May 2018 tenant reported that roaches is taking over. I phoned today to report the problem and they send someone to come have a look. They declined my request for further treatment because according to them the work was done on a different flat unit and that I now will have to pay again for any further treatment on this here mentioned flat unit. The manager gave me a mouthful when I spoke to him again saying I had no manners for getting mad at their response. All correspondence between me and tenant is available so the quote here mentioned.