Duplex printing is not

Drum bought in February 2013, use only in January 2014 needed: drum fails at the first duplexing. Each duplex job, the single-sided paper stuck in the printer: drum must be removed to clear paper jams. After 2 attempts to drum bumps, roughness etc. investigated a sticker removed, surface smooth and unobtrusive: nevertheless duplex printing does not work. Otherwise only made simple DINA4 printouts. Drum returns.
For me, the drum was not useful, so only 1 star, because unproblematic return and otherwise good quality of the drum in the Simple Pressure 2 star so.