As was pointed out to you in another thread you posted - buying "stolen" phones off Ebay gives you no options.
I thought Ebay now had some sort of buyer's protection policy.
Hi diggerty! It looks like you've got a pretty active thread on the same general topic here - will a blacklisted iPhone on T-Mobile work in the uk? - but to speak to this question directly, for legal privacy reasons, we'll only be able to release the balance owed on a device to the account holder. Essentially, you'd need to ask the person you purchased the phone from to contact T-Mobile and find out what balance is owed for the device.