I'm still not sure what you did. What this two separate items with a "Make An Offer" option? Or were these two separate "Buy Now" items with a "Make An Offer" option? It sure sounds like you bought two separate non-auction items, because you made two independent offers for two separate items. Maybe?
Regardless you still have to complete the transactions by making the payments yourself. Not getting this sorted out won't result in eBay taking your money. But not paying for an item you... did whatever you did to/for will cause your eBay account to possibly get suspended.
If the seller won't let you out of the... whatever you did you can contact eBay and see if they will accept the "mistake" defense. But they don't have to either. They may just view it as yet another case of buyer's remorse.
Be more careful.
