Buying tickets off of eBay was a mistake. Retailers on eBay are not approved resellers of WDW tickets. All WDW tickets clearly indicate that they are "non transferrable", meaning that they are intended to be used by one individual after purchasing from WDW or an approved reseller. The one thing I would suggest you NOT do is walk up to a ticket window at WDW and tell the agent "I purchased these tickets off of eBay and want to know if they are any good." Because of the "non transferrable" clause, WDW can confiscate tickets if there is sufficient proof that they were involved in an inappropriate transaction.
Also, I've never heard of a "two day hopper" pass, so I'm hoping, for your sake, that you actually bought a partially-used multi day hopper.
I'm not trying to unnecessarily worry you, but those are the facts.
With regard to using the passes, if they are legitimate park hopper tickets with the magnetic stripe on the back, all you need to do is go to a park entrance, slide the ticket through the reader, and hope for the best. The admission information is electronically encoded on the ticket, so honestly you have no way of verifying the true status of the ticket until you arrive. Disney will not do this over the phone, simply because it would encourage the type of transaction that you have apparently completed. If the tickets end up having fewer days available than you were told, you will be turned away at the gate and have zero recourse.