unfriendly customer policy

I purchased a pair of BMW sneakers on the 18th Feb 2016. The sneakers were of the incorrect size , I went back the next day (19 Feb 2016) for a refund because I purchased the sneaker directly from BMW lifestyle at a cheaper price. However, the store declined my request for a refund , I was forced to take another pair I'm not happy with, the logo is damage, the assistant claims not to have another pair of the required size. The manager was of no assistance and the cashier is not suitable for your business because she lies about policies she supposedly informed me about.