Engine swap gone wrong.. Options

[SiriusVirus]

So in june of last year I decided to bring my celica back by paying to swap an engine in because of rod knock. 1500$ all together to have the car back and running. In september I was driving to school and my car died and began having rod knock sounds again... I called and chewed out the shop demanding they swap another engine. I drove with my friend to pick up my car and first i noticed my over drive was flickering on and off (I had my family mechanic fix it just a plug not put in all the way) probably a warning sign they did a crap job. I drove this car all the way up until now and then I realized in my garage I had oil dripping on the floor. I took my car to my family mechanic right away. Hes been with the car all week and told me there is oil all over the engine bay and he has to power wash the whole thing to figure out where its coming from. I spoke to him today and he told me the engine was never properly sealed its almost as though they went to a junk yard and just dropped it in and never even cleaned the engine bay. Those mechanics are claiming the warranty on their work is up after 3 months. Paying to get a rebuilt engine and it only lasting for 1 oil change is ridiculous! Im wondering should I take them to small claims court if they keep refusing to repair this for free? My mechanic told me it would cost him 800$ at the least to seal the engine its leaking from the block and cylinders.

So I have had a total of 3 engines in this car. Let me know what you guys think is the best course of action

Thanks in advance.