ENGINE LOCKING ISSUES

Mechanic guys advised I buy, 5litre oil and head gasket and they took the top for skimming(the mechanic guys?)
Did all that, gave them R300 to skim the top and actually bought the whole top gasket set, Friday last week they
brought it back but had what they called teppex(not sure if I’m spelling it correctly) but it made this funny sound
and they advised that they were gonna come take it following day to tighten the teppex, they did come back to
fetch it and brought it back...(They charged me R600 labour)

The sound was better but I noticed that it wasn’t the same as before and it was like cutting itself, told them and we
made arrangements that I was gonna bring it back this Sat, yesterday on my way to work the car did the same thing and locked itself, exactly the same thing that happened before, some Indian guy came to assist and advised that the car was never skimmed hence it’s licking and also noticed that its body valve was loose and advised that I take it back
to them and tell them that it’s returned job and not pay them.

Did that and they advised that leakage wouldn’t cause it to lock the engine and advised that I must leave it to them
so that they check the pistols and would call me today to advise what the problem is, asked them as to why was it leaking if it was skimmed they stressed on the fact that it was skimmed which is why the engine was turning when
they returned it so the problem is no longer with the top but they’ll have to strip the whole engine.

Now mom called them this morning and advised them not to do anything on the car, she told them to replace the top cover and I’ll come fetch the car from them later on, She actually advised that I rather take it to GM now my problem is, I cant afford to take it there right now coz they’ll slaat me with one crazy price.

If you have connections as to who can fix it for me please advise as I really need to sell it, I tried selling it sometime last year via dealerships and they told me about the book values and all that and the prices they offered were really low, some even suggested that I re-do the whole body work for me to get atleast a reasonable price!