Bought gift cards at Target and the inside gift card doesn't match the serial number on the outside

I bought some Apple gift cards from target to take advantage of the special offer they had of getting $10 gc for every $100 Apple gc bought. When I opened them, the inside gc didn't match the number outside. There was only a $25 one inside. After searching online, I find that this isn't an isolated incident, what phone number should I call to take care of this asap?