Poulan Pro (10") 1.5-HP Electric Pruner and Pole Saw

Good evening. Last month I purchased from Lowe's Poulan electric pole chain saw (PLN 1510 with a 1.5 HP). I used it several times and liked it until a few days ago when it fell to the ground on some large rocks. A part cracked. I do not know the name of this part and it is not labeled on the parts diagram on line. It is the big black connecting part on the pole length that has the compresion threads inside. That part is turned to extend or lengthen the pole. I went to a Big Box store for a repalcement part, but they said that they were not able to help me. I do not want to return the pole chain saw, I just need the part and instructions on how to place that part on correctly. That particular part had to be pre-assembled at the factory and had no possible way for the user to replace that very vital part. Can you please help me with getting this problem resolved?

I need a replacement chain for an OREGON 8" 91VG036X....fit WEN pole saw. Is it available or is there an alternative?