I ended bringing it to a repair shop in London to have a look at it...Not sure it's the parts of the drone.Recalibrated everything but the problem appears randomly...(really annoying)..I had new propellers and the drone worked fine on several videos.
Thanks for that..looking at videos online,the jello effect is sort of permanent...mine is not...it just pops up for a second (or a few when really bad)..otherwise,the drone can work and film smoothly