uhh explosion may occur??!!

Kay, wel lI psoted how my car has been chugging gas back since I got my replcement motor in about 3 weeks ago. It has fresh oil in it when it was put in, and the whole bit. Today, my dad is quite good with cars, he checks my oil, its as runny as water and about 80% gas. Somehow gas is getting into my oil, should I tell the Wreckers to put a different engine in because everyone I talked to today say it means it's pooched and shouldnt bother fixing it. I have 3 month warranty on this anyways, engine and labour so its free either way. Let me know what you guys think I will be calling them in the morning to see what's up.

next engine do a compression check before the install, it`ll save alot of hassles later .Unless of cousre there are other underlying issues .