Airtel — faulty charge amount from app/ website , non refund of money and mobile not recharged

Address:

New Delhi, Delhi, 110070

I am trying since past two weeks to recharge my cell phone ([protected]) of amount rs 500 (Talktime only) from airtel app and websites. On doing so an automatic coupon of rs 50 is applied making the recharge of rs 450 which i am unable to modify.
I tried doing so 3 times in past 2 weeks and every time i do so my credit card is charged of amount rs 450 but my mobile doesn't reflects that balance and then i get a message of transaction failed.
I have many grievances with airtel:
1) if rs 450 is an invalid recharge amount why does airtel apply a rs 50 coupon on my rs 500 recharge and make it un-workable all the time
2) amount is deducted immediately but its not refunded immediately and it takes 7 to 10 days for airtel to refund it.
3) i needed that talktime to make important calls internationally but unfortunately because of airtel i have lost on them and airtel has made me to suffer
4) airtel's customer service representatives are the worst, they only have standard answers with no solution and in fact they are one of the reasons that customers want to leave airtel
To conclude, airtel is the market leader with one of the worst team, app and websites and it is full unethical and immoral practices which makes its customers to lose on their personal as well business because of their mismanagement, misbehaved team and poor services