Reliance Jio Infocomm — Refund not received on jio fiber disconnection

Have disconnected my jiofibre connection on 26 Feb and as per policy refund of 2500 was to be credited in my account within 14 days it's 3 months now but I have not received refund..every time the customer care says refund deposit has failed...how is that possible when I have submitted cancelled cheque.
New service id (SR00001AVS0L)