Fuse 13 and 14 keep blowing

[BlackShadowTSi]

I'm trying to help a friend she has a 2001 Passat 1.8t auto.
She got it a couple of weeks ago and notice that one of the brake lights was blown, so she went ahead and replaced it, but the people at the auto store gave her the wrong bulb she didn't know and forced it to fit. But that is not all, even the bulb went in stop lights were still not working.
Later the same week she went to put fuel in the car, and when she went to start it up again, the car wouldn't turn over. She had to tow it home and then is when she called me, I checked the fuses and found that #13 and #14 were blown, replaced them and the car started right up, but only one side of the tail lights was working (turn signals and running lights) but it had no stop lights. As soon as you touch the brakes fuse #13 blows.
Now fuse #14 keeps blowing everytime she touches the buttom to open the gas tank. And #13 everytime she touches the brakes.
Trying to isolate the problem I took both of the tail light sockets and left the passenger side disconected and the fuse didn't blew, then plugged that one on and left the driver side disconnected and the fuse didn't blew. but the stop lights were still not working.
I'm kind of lost right now because I'm not that familiar with VW's .
On the side note, she had an aftermarket radio installed (one of those fancy ones with tv and such), since I didn't trust the installer I took it out but everything seams to be fine and the fuse keeps blowing.

I would really appresiate some help, this is her only car so I would like to get it running ASAP

Thanks in advance

Diego