Bad service at Carnival Bosch car service

I took my car on the 5th May for service. i parked my car for 7 days as i flew to CPT on business trip. when i came back to drive the car, there was red oil light. there was no leaks in the garage. i had to put 1 pint of oil to see if there will be a change. indeed the light went off after the 2nd pint of oil. and it showed that i must put more oil. i went to the garage, and met a tall coloured guy who was very rude. he didnt even tell me his name, and he dsnt know the owner of the garage where he works. i left my number with him for the owner to contact me and its 2 weeks now without any call. i need Bosch Car service head office to take this matter up further. i have taken picture of the dashboard as proof.