1997 Chevy Cavalier one problem after another

I recently had my valve cover gaskets change and had the timing chin replace. Since carrying my car to a chevrolet dealer to have the work performed, it's been one problem after another. They bent my fuel injector wire, and did not perform work on a part I wanted them to, the area where you place the oil was leaking but they only applied a sealant, until I carried the car back. The work was performedbut, since that ime, my transmission is leaking. I am not having problem with puttin the car in gear, but oil is leaking. What does the transmission have to do with the timing being changed and what do you think the problem could be? Thanks for helping