Woodland — payment issue

Address:

Bangalore, Karnataka, 560066

I have purchased shoe on[protected] which was on discount. I paid amount of rs 2061 for it. As it has some leather crack i asked for replacement. When the replaced shoe came the shopkeeper is demanding for extra money saying the discount value has got changed. I don't understand, as i have already paid the amount why should i have to again for the replacement shoe. I have attached copy of bill and repair slip.