Big Business delaying to pay back their customer

Mondo sd me a product that I didn't need and I canceled the contract within the specified cool off period, but I struggled for 4 months to get a refund from them. The reasons given were so flimsy and one could sense that even the senior staff were trying to kick the can down the road. My case was classic case of wrong product sold and it didn't need any hesitations from their part becuase the recorded messages confirmed that.