I am a bit puzzled about the different ways we can continue the phrase which starts with "I would appreciate if..." : 1) I would appreciate if you sent me a refund. 2) I would appreciate if you would send me a refund. 3) I would appreciate if you send me a refund. As far as I can understand, the first and the second variants are grammatically absolutely correct, the second variand ("would send") implying the willingness on the part of "you". Is it right? The third variant ("send") is incorrect, in my humble opinion. Because "I would appreciate" is an unreal conditional, and "if you send me" is real conditional. Their combination seems illogical. Or is it acceptable? The search in the google gives examples of all types, but native English speakers can also make mistakes. So, I am interested whether the third variant ("I would appreciate if you send me a refund.") is: a) grammatically and stylistically correct; b) a grammar mistake; c) bad style. Thank you in advance!