Bharat Sanchar Nigam [BSNL] — about getting refund of rs2957 of my deposited landline number [protected]

I have surrendered my landline no [protected] at ozar bsnl office 0n 14/04/2017 due to shiffting of house from ozar township to ozar. After that i got one message from your department that dear customer your ph no [protected], a/c no[protected] has been billed with rs -2957 on 24 may 17 and due date is 12 june 2017. This means i should get refund above amount.
But still date i did not reacived any amount from your department. One of my friend l. S khairnar landline no [protected] has also surrendered his number on same date, we both have surrendered our landline on same day. But he got his refund two month back. I several times contacted at your office {cashier [protected]}but all times they replied that for such things it takes time, we have send your proposal to mumbai.
Sir if we both friend have surrendered our landline on same day and he had got refund his amount two month before then what is the problem for my amount refund. Sir pl look in to my matter and do the needful help.
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Thanks & regards
Anil j. Patel
Jyotirgamaya'plot no 06 panchawad nagar,
Ozar, tal. Niphad dist nasik
[protected]