Which osd did you have? All RTH autopilots I know of require extensive setups and careful calibration to work with a given aircraft. Sorry I know the horse it out of the barn already but it is what it is.
Alot of us have lost planes, and after that we either quit or get more diligent. I recommend a beacon such as this for future long range flights:
Also extensively test RTH LOS before attempting to try it long range.