Bunch of ****** and will never ever recommend so called Fix it !!!!!

I work for company as a General Manager for short term letting apartments and have used Fix it for repairs to a Smeg stove . We have called them in for repair to the unit and they came to access the unit and gave a quote of around R15 000 to repair a error which was on the screen. Our company then paid the amount to have it repaired in January 2019 an amount of R15000 and estimated time for repairs was around 30 working days and they gave us a loan unit which is a cheaper brand ( Bosch ) second hand unit. I spoke to 1 of the directors or so called Seniors ( Zahier) and he informed me it can be fixed and just waiting on the part to be delivered. I had to keep n following up and up till now nothing has been done on the issue . We paid R15000 to a bunch of ****** !!!!They refuse to refund us back and actually told us that when the new part arrived that it blew something else which is not our problem but actually the techician fault and do not know why the customer must pay for it and now wants us to pay another 2 or R3000 to get it fixed . I am still waiting for someone to resolve this matter !!!! Can someone call me back urgently.