Unnecessary call out fee????

I have been having tons of issues with my ADSL connectivity being slow during late afternoons and night. This has been communicated tons of times with calls closed. Still nothing done even though tests performed and solution available. Technicians were onsite with feedback that nothing can be done. I have many times mentioned that a technician cannot do anything as its congestion, however Telkom continues to get technicians to me that respond the same way as before - \Sorry Sir its congestion". The last technician onsite had first had experience with my issues"