Yes it seems that you have an extension problem...but not if you have changed it for new ones 6 or 7 times.....once yes, twice doubtful..no way 6 times.....

Did you swap your servo one wing to the other? Possibly mixing them up on reinstallation?

If you didn't then lets look at whats left...assumming you used new extensions...you could be just moving the problem around if you didn't. then you have either a bad servo, or a dirty connector on the servo...clean it with contact cleaner or alcohol. A switch can cause intermittent problems like you are having...The Y extension out of the receiver is most likly the problem. Lastly the receiver itself....

By the way both aileron sevos are the same brand and model aren't they...they have to be

Hang in there you will be back in the air soon