Sai Enterprises Mumbai - Wrongly charged amount for without replacement of parts plus Gas charging of our Bosch Refrigerator

My Bosch refrigerator was not working hence my daughter called service center no. searched from google & they have deputed person from Sai Enterprises, Mumbai for the said job. He has charged for the followings -
*. DSP Sensor - ****/- in the model there is no requirement of this sensor still he has charged for this . It is confirmed by BOSCH service Engineer when we called him.
*. Gas charging - ****/- he has not charged Gas still he has charged amount for the same. It is also confirmed by BOSCH company Service Engineer when we called.
*. Dryer replacement - ****/- this is also not replaced but stilled charged.
After doing the above work my fridge was not working hence we called Kohinoor show room person who has given us exact correct no. of BOSCH service center. Hence we called their Engineer who has informed the above to us.
When we called person from SAI ENTERPRISES, he has promised that they will refund my amount immediately but fact is that till after passing one week there is no response from them & now they are not lifting my phone hence registering this complaint for your doing the needful. I am attaching herewith their bill copy for your doing the needful.
Looking forward to your kind urgent action in the matter.
Sanjeev Bawage, B*/****, Green Acres-III, Waghbil road, off GB road, Thane-West
Cell no. **********