Please forgive me for being impolite and not showing up.
You took the trouble to contact me but I didn't show up, I'm very about for that.
Please forgive me for being impolite and not showing up.
"姿も見せない(not show up) 失礼(impolite) な僕をどうか許してください" という意味です.
You took the trouble to contact me but I didn't show up, I'm very sorry about that.
"せっかく君が(you took the trouble) 連絡をくれた(to contact me)のに姿も見せなかった、どうか許してください" という意味です.
モロッコ 
