Wonder if anyone can help. Less than 12 months ago I purchased a 4 shot to go with my two 2 shots. It has never really worked well and hardly been used. However circumstances are such that I want to use it regularly and the 4th bumper - furthest from the receiver wont work. The little arm goes backwards. Have tried two new servos and still does not work. Have sent email to Bumperboy but don't know how long they will take to reply. Sending the unit back to US is not really an option. Any ideas would be much appreciated!