It is very Possible that is was cheaper to ship Individually then it was to combine shipping ....
If you purchase items being told you would pay a certain price then the seller should honor it but doesn't have to...
If you purchased it thinking it would be cheaper without clarifying it then pay up ..
Combined shipping does not mean cheaper so always clarify with seller...
I gave this example to someone earlier ... if you buy 3 DVDs off me it is roughly $5 if you want me to combine them and ship together I have to upgrade shipping method and that almost doubles the cost ....