Car damage dispute question?

my mom has this moderate sized RV(Rialto) and was backing into a parking space. when we got out, the owners of the car we parked next to told us we dented their car. it was a pretty tight nit parking lot and it we may of gotten really close to were it looked like the RV hit it. i was in the RV the whole time and didnt even feel a nudge. my mom has a camera in the back of the car that assists with backing into places and it she didnt see any part of the car ramming into their car. my grandma who was at the side the cars supposedly hit didnt see us hitting their car. The people said there was a old dent there before, and that we made it worse. i looked at there car and our car and didnt se any evidence that we hit it. the scratches had white paint over them and the lower part of the RV is grey and plastic. there was no damage or any scuffs to the RV. im not an expert on this stuff so i dont know if there just lying to get money from us or if we really hit their car without noticing. A cop came and examined the dent and our car and just told us to leave it up to an insurance investigation. the lady of the other car even said there was a dent on her car before and never made a claim on it, if that really matters. Anyways what do you think the insurance companies will do? Will they be like, its only a dent and theres no proof? just would like some input on the situation.