I had one take several months and never was delivered. After a couple of weeks, we tracked it to the US post office where my customer lived in Califormia but by the time he went there (2-days later) their paperwork indicated that it had been shipped out however it didnt say where it had been shipped to.
So I filed my claim after refunding my customer about 45 days after I shipped the product out and received my refund cheque. A little over 3-months after I shipped the product out, along comes CP Express returning the package to me with black pen indicating "Dead Mail" on the package.
Its rare that it happens, fortunatley, but it can happen.
I also had a strange incident last year. I shipped out 2 violins to the same person in Texas. They were shipped the same day by Express Post, to the same person at the same address with each package almost identical in weight and size.
The first one arrives within 4 days and the second slightly over 4-weeks.
Malcolm