Europcar dispute in inappropriate charges

When hiring Europcar hire.. I was asked to take photos of the marks cracthes and dents However there was a dent on the passenger back door, which I called the guy and with an attitude he said he knew about it

However now that I took the car back to europcar They are holding my deposit with out informing me When queried now, I get told the dent charge is R3000 plus

Is this a money making schem in trying to cover up your cost