Earth leakage poor service

Provided an electrical COC for a house I purchased and just after I moved in the earth leakage continued to trip after load shedding, can in and replaced the earth leakage and left without mention of charges to follow. Later sent an invoice to the estate agent for R1500 to replace the earth leakage. Says they do not guarantee the COC when the bill was queried, and then came to my home and removed the ear leakage leaving me with no power! Unacceptable service.