Contact mods in first instance -then put request out for help from members. Worked for me with a tardy individual who is a fairly regular contributor on this site!
I think as a rule of thumb, goods should be posted within a week and good communication is key. I agree that messages still in the outbox when you are waiting for a part is worrying!
Advice from the mods re getting real information - address, phone no etc is worth it for anything vaguely valuable!