Forced to take a gift voucher instead of refund via cash or eft!

I find it very odd, how I can purchase something online, using my debit card and then when I return a portion of it, I am forced to have it be put in a gift voucher because I didn't have my card with me! I used cash, but I am told I am not getting it and forced to accept a voucher, that I can only use in-store! What nonsense is this??? You guys were quick to take my money out of my account but have a problem replacing it when I am unhappy with the products I received, Mr. Price is no longer the place to shop these days!