take the internal pice you have in your hand to the hardware store and buy a threaded elbow you can attach. and take out the broken pice in the pump of coarse
Email the person you bought it off of thru ebay. Explain what happen and go from there.
its ok.But thxs for the help anyway broSorry can't help ya there, I don't use ebay at all. Might check your regular email address inbox, might be something there? Good luck.