Probably raised from seed of a pink dogwood, thus the touch of pink. Or, yes, it is the wrong item. Another thing that should be mentioned is the grafting of pink dogwoods onto white seedlings, there are many two-in-one trees here where the white rootstock has been allowed to grow up through the pink scion and produce its own flowers. (Pink-and-white grafted Japanese cherries are also common).

Wait until it has produced a full head of bloom or is otherwise farther along before deciding it's a lemon. Possibly the one initial effort was not completely representative.

Probably, you got a mislabeled one. If it is important to you, and if you still have the receipt, and if you have a photo showing the flower color (the last may or may not be necessary), then I would go back to whoever sold it to you, and complain. They SHOULD give you a pink one or refund most or all of your money. If you don't really care, and it's growing well, enjoy it, and let the matter go. You might want to give the seller a heads up that there is a problem, just for their information, but that's up to you. To my knowledge, soil acidity or lack thereof has no effect on dogwood bloom color - it's only certain hydrangeas that change color according to pH.