Threatened by company that tried to de***** me!

All of last week my tenant waited for a plumber who was a no show. By Thursday (sitting with an irate tenant) HE had shown up for 2 & half hours and i told Pieter i would have to find someone else then his wife who had answered the phone told me it would be 5000 for the work done. Mind you, the work done was to rip my shower and my ceiling downstairs and apply fibre glass and sealant to the shower floor. On Friday afternoon he sent an SMS to say can i just pay him 3500 and find someone else?! I tell him I'm happy to pay for the hours and cost of the material and call it quits and pay him 2500 then he says then it will be 3200. I insist on seeing slips and he tells me he will send slips as proof. I get the slips today and i only owe him 1000 for materials & they added an unrelated slip from this past saturday? for 800? i duly paid the hours and the 1000 for materials which was 2485 and they insist on getting VAT on that? At no point did they apologise for trying to de***** me instead I've been threatened that they are going to break into my house and smash the shower. This is after sealant was left on my tiles and they are damaged?! and Debbie calls and YELLS at me?! a customer?!