Pella sliding door handle

My patio sliding door Pella handles will not screw together, so I'm looking for replacement. The door My patio sliding door Pella handles will not screw together, so I'm looking for replacement. The door looks wood on outside, but it's kind of a metal frame on the side part of it wood on the inside., but it's kind of a metal frame on the side part of it. The outer door part has the numbers 40644 C IIone on the inner where it goes against the door and then the inner door handle has the numbers 40643 58 I one or maybe tonight and it says rollscreen RD 1991