What does one do when a limo double books for a wedding?

Depending on who booked their event first - your friend has a right to a full refund and a recommendation. A lot of limo companies book multiple events in the same day but have the coverage to get everyone where they need to be. The limo company should have contacts to help you find someone else. You could always rent a large car and have someone drive it for you. Other than that, you'd have to find another company. I would definitely make your dislike for the situation known and see if the limo company is willing to give you something in return.

Did she sign a contract already, why was the other wedding chosen over hers? If a contract was signed then they are responsible for finding her a limo and providing a service...even if they have to work with another company from a nearby town. It was their mistake and unless they want to get sued in the end, they will figure out something for her. She can not be inconvenienced for their oversight. Contracts are a serious thing and once they are signed they have to be upheld one way or another. Good luck to you and your friend!

If it's possible she should call her local television station and see if they have a "trouble shooter" who reports on business who don't do as they should. They usually get results and it's VERY negative publicity for the limo company! I hope she can get this resolved easily and in a timely fashion.

I would call the limo company, with contract in hand. I would demand they compansate the charges.

How about renting a car and having a friend drive if you plan on drinking

go over to the company, give them hell and DEMAND they compensate you

If she has a contract, it is their problem not hers. They have to accomodate her.

Obviously it's a sign that the marriage is not going to work out. I would call it off with your fiancee immediately.