Mahindra And Mahindra — for not refund my payment

Address:

Nagpur, Maharashtra, 440001

Hi sir,
Ill go to your service station unnati motors, kamthi road, nagpur for servicing my xuv 500 on 15/02/2019 at the time of servicing they give me estimate of rs 5500+gst, without ask they change my break paid and coolant, wheel alignment and give me bill of rs 18000.
Before ill already change my break paid and they told me 30000 km run that part but he change after 12000 km without intimate me, when ill said him they told me ill return your amount in your account and after 15 days they deny for return my money i am having recording of that conversation, so what can i do, ill go to consumer forum or any other place..