Assaulted and humaliated by staff

i bought an engine at Joe's on the 26 of January because my previous one busted. i later sent the engine to my mechanic and a few days later he told me that they sold me the wrong engine. i then returned to Joe's and spoke to Mohammed . he told me that they cannot refund me the money but will get me the engine i asked for. yesterday i went back again to know the outcome and the guys there were rude and loud. the one guy came and punched in the face whilst my brother took a video of the incident. When they saw he was taking a video they went and deleted the video and broke his phone.

I am totally shattered about the service and did not think it will get this physical. the engine that was sold to me was old and used.

please help because this is getting out of hand and i need my engine or money back so i can buy another other, I'm really being inconvenienced because the car is for work and this thing is straneous.

Thank you