Good way is to talk to your Seller.
Related to damage, instead of raising about combined shipping, please explain him that your received damaged items and ask him for compensation or replacement. He will certainly help you else you can raise with eBay customer care for further guidance.
Related to combined shipping, you can claim partial refund to the extent of combined savings with the help of Seller itself easily.
Normally, Sellers will provide gifts along with the pack in such cases.
Note that always Seller may not get shipping benefit all the time, by combining the size of parcel increases along with weight.
As rajelectroniks said, he is correct.
Regards