Cut a hole in my fuel tank

Back in July my fuel pump went out on me and to make a long story short. this so-called mechanic was going to put it in for me he does there's no access panel for my back seat or trunk. so I know they have to drop my tank come to find out if you days ago because I've had this bad gas mileage can't fill my tank up because of the gas smell my fuel gauge doesn't work. so about 5 days ago I pulled back everything out of my car my my backrest night seat cushion for back seat because there was metal shavings in my trunk. Come to find out there's not one cut but there's two cuts in they are so sloppy in one of the cuts they cut right into my tank. So yeah please tell me what I can do? he did tell me he would get me a new tank okay but what does that do for the body of my car it's messed up?