Worst dealer I've ever come across

I took in my car for major service at VW brits and when i took it there, it had no problems, it was there from friday the 9 of October till monday the 12th... when i got it back it was leaking coolant, i informed the people and accepted that the messed up and said i should bring it in and they'll fix it... now they call me and tell the radiator is cracked and that i should pay R13 000 for damages the caused