Lighting System Issue

I recently had my headlight switch changed by a service center because I have a warranty on my 2000 Jimmy. They did this to fix my fog lights. That night when my headlights came on I had no fog lights, no interior lights, no tallights and only the left high-beam. I change the parking lamp fuse and figured it had just blown once, no big deal. However the fuse has now blown multiple times since I keep having to change it for temporary taillights. Does anyone have an idea of what it might be? I thought they might have left a ground disconnected but I really have no clue. Any help is appreciated. I just want to know what to tell them when I take it back on Monday. Thanks