Mechanical car workshop warning

I took my Mazda BT50 to Carformance mechanical repairs in Vereeniging with a noise inside the engine in December 2020 -The owner informed me that they were RMI four star rated and highly able to attend to the problem on my vehicle- After three wrong findings of what exactly was wrong with my vehicle, the owner Jannie forced me to pay them R3 000-00 before I could remove my vehicle from their workshop - I was never given a written quotation or invoice or any form of paper work - My vehicles engine was stripped, after I gave them very clear instructions not to do so - All the removed parts was placed on the back of my vehicle - Be warned of this mechanical workshop and the manor which they operate their business