Pothole ruined stock radio

Question

I drove over a pothole and lost reception to my stock radio on my 2005 Pontiac G6 GT.  There was EXCESSIVE static on all major radio stations.  I took it to the dealership and they replaced the antenna module it seemed to slightly fix the problem.  Then 2 days later we were back to where we started.  The dealership then replaced the entire car radio thinking it was something internal in the radio.  I picked up my car and then the next day the reception was AWFUL!  They have no idea how to fix it and it is driving me crazy.  Do you have any ideas about what the problem might be?  Thank you!