Judy,
We run "free shipping" sales periodically.
When a buyer purchases multiple items, of which one is "free" shipping, the items with shipping costs are invoiced with the reduced, combined, shipping rate.
When everything is paid for, we ship. Buyers are usually surprised (and grateful) that they only have to pay the reduced shipping cost on the other items.
Don't know how you handle combined shipping when one item is "free" but if your buyer is not responding and has paid for full shipping on the other items, just ship them.
Make sure you duplicate your communications via eBay messaging as a surprising amount of mail sent through a proprietary client is caught in spam filters - "Gmail is notorious for that.
Xena