Money deducted from my account but haven’t received refund till now

Money deducted from my account but haven’t received refund till now
I have travelled from Guwahati to Bombay through Indigo (Flight no-6E-6526)on 01st September PNR(G44GRB).I have having 18 kilograms of extra luggage .So I was told to pay 10900 rupees .When I paid the amount through UPI the amount got debited from my account and they told that amount was not received in counters of Guwahati airpot .Then they told to pay again as they haven’t received the amount .I paid the amount again through debit card of 10900 again .This time amount got debited and got credited to them .They told that the payment which I send through Upi ,I will get the refund within 48 hours .If payment is successful and has reach indigo the refund will be reach to me in 48 hours .It has been 9 days I haven’t received the amount .I have every proof regarding this matter .
I am a student and amount of 10900 is very precious to me .Customer care is just saying wait for 24-48 hours but I haven’t received the refund .Case no is 04397252.Please do the needful