Airtel — Fastag issue and reissue

Address:

Airtel store - Address: Shop No, 565, KA/89, Kanpur Rd, Muslim Nagar, Alambagh, Lucknow, Uttar Pradesh 226005.

I was cheated by the Alambagh Airtel store - Address: Shop No, 565, KA/89, Kanpur Rd, Muslim Nagar, Alambagh, Lucknow, Uttar Pradesh 226005. They took 500 INR to issue Fastag. Took Cash only. Did not provide a receipt when asked. Entered the vehicle number incorrect in their database despite filling the form 4 times and providing the RC copy. This resulted in Fastag getting blacklisted at toll. Paid again for getting it reissued and still it is in RC validation pending status. What actions can be taken again such fraud and lousy service?