Reliance Digital — Refund not received after 4 months for a canceled product.

On 1st June 2021 I ordered an Apple 20W USB-C 20 Watts Fast Charging Power Adapter through UPI payment from Reliance Digital, Ground, First & Second Floor, 20, 22B, G T
Road, Uni-mark Square, Opp. Uttarapar Housing Estate, Uttarapara 712232, West Bengal, Ph: [protected] / [protected]
Email:[protected]@zmail.ril.com, Mode was pick at store. my Order No. was RDF12324908.
I tried to cancel the order on the day of order. But due to some website problem i was unable to do so. I talked with their customer care executive who informed me that its not a problem. The order will get automatically canceled if i don't pick the product from the store with in 15 days.
But after 15 days I didn't receive any refund.
I send Multiple mail to Reliance Digital about this matter but they didn't took any step.
Suddenly on 21st July I received a mail from Reliance Digital that I have picked up that product from the store which I haven't. Again I have Informed them about that but they are very reluctant to solve this matter.
I want my refund As soon as possible. It's almost 4 month and 15 days.