Alamo rent a car Enterprise rent a car $700 Bill for damage done 2 months before I rented the car! Internet

One month after my trip to the US I received a letter from a debt collector demanding nearly $800 for damage done to a rental from Alamo.

I demanded to see evidence as the car was fine when I left it in the lot. They sent copies of the slip filled out and the photos in pdf format - which conveniently prevents anyone confirming when they were taken.

I requested the original photos, Alamo flat out refused, and said they didn't have them. After 9 increasingly strident demands they gave me a screen shot of 2 photos, with the edge conveniently cutting off the time, only showing the date.

Finally they sent me the shots - according to the exif info they were taken in October 2012 - I rented the car in January!

Alamo said that's impossible, that its a valid claim and it will be pursued as such.

The (lack of) evidence is on my side, but do I really have to take these guys to court from the other side of the planet to solve this?

Any advice greatly appreciated, and to any consumers out there, if someone tries to hand you a set of keys for an Alamo car out there run away!!