No after sales service whatsoever

I purchased a Mitsibishi Mirage in April this year from TATA Pretoria North which came with a service plan of R6000 which was included in the price. I was also told that the vehicle had just been serviced but there is no invoice or indicate in the service booklet that it went for a service this year. I now want to take the vehicle for a service but I don't know where to take it to, Mitsibishi Paarden Island are wanting to find out with who is the service plan with as it could be an extended service plan as the car has now 59000 on the clock. I have been emailing TATA I have called their customer care line - it just rings and I get no response. Seeing that I paid R6000 for the service plan I would like to take my car for a service. Please can someone assist me.