Review Bad Service Lazarus kia Centurion

Took my car yesterday for them to check if the radiator head any leaks. The car was fine when I dropped it of. At 4 they replaced the radiator cap en fluid. When I arrived home the fluid boiled. Took it back this morning and now the whole engine must be stripped to see if anything in the gasket head got hurt. Not sure what this will cost me and I don't know how they can prove to me that what they did - did not cause more issues. And why my car had to be there from 7 in the morning and only at 4 when I arrived they quickly replaced the radiator cap and fluid? Reception is rude - with my last service, my whole service book went missing. No record of all my services anymore.