Decathlon — not getting refund

Address:

Dehradun, Uttarakhand, 248001

I returned flx cricket track paint at decathlon dehradun two months ago. Sale's person told me that amount would adjust on your next purchase. Today i was on cash ccounter for my next purchase and asked cashier to adjust that amount but he refused and reply politely that it is only possible within 24 hours.
Is this fun.
I never expect this type of policy from a leading brand