TechnoPro disgusting customer service

Bought a 49mm UV filter from Technopro, only to discover that it would not fit on my camera as I need an adaptor to fit a filter, and the filter size required is 67mm. I contacted Technopro and requested that I return the 49mm filter and they supply me with the correct sized 67mm filter, and would pay the difference in price plus any handling charges that might be applicable. The 49mm filter is in its original packaging, unused not damaged in any way other that the seal on the filter case being opened when i tried fitting it on my camera. Technopro has refused to take the 49mm filter back and have requested that I place my order with them for the 67mm UV filter which they will charge me full price for again. This is not acceptable and EXTREMELY POOR CUSTOMER SERVICE