F450 no start

Took my '08 F450 super duty into a reputable snow plow dealership and had them install a brand new plow on my truck. They phoned me this morning to say that the truck's security system does not recognize the key, possibly caused by the fact that they had to disconnect the battery during the plow install. So now my truck is stuck at their shop !
Any ideas on this issue ? Just hoping I don't have to get it towed to a Ford dealership.

Had the truck towed to the local Ford dealer and they discovered that it was an after market remote starter that was causing this problem. I purchased the truck used and did not know it had this installed, all I had were the the stock keys and remotes to unlock the doors. Got them to remove the darn thing and now my truck is working fine.