As long as Ebay and Paypal have got their cut, they don't care too much about you. Shure, they will help after a fasion, make sugestions as to what to try but they won't get over involved. The proof is all on your side. You canot prove that you did not break your banjo yourselve, so you have no proof that it was broken when it arrived. Have a go but it's all on you.