The piece I have that connects the two shoulders (https://youtu.be/B8N2KAf8p28?t=34) have two holes on either side of the wood, not two and three like in the part photo in the assembly instructions (see below). That makes it shorter and not long enough to reach. If I got the wrong size shipped, how do I get right size?
Y1 should enter the flat slot on the shoulder piece, not the tilted slot.