Shocking service

Shocking service from this company. Done work on the Friday, claimed tested it and all worked. At the end of the day nothing works, comes out the Saturday and then accused the people of not knowing how to use a remote button. Claims to have retested it and all works. Next day does not work and then when he comes out claims system cannot do what he claimed he had fixed twice and tested (if it could not be done, how was he able to test twice!) Proceeds to install another system after claiming to have cleared with owners of building and the tenant. which they then said he never ever spoke to them about and then bills for work never approved. So the work he originally done and was paid for does not work and now wants payment for work which was never approved.