I own two Phantom 4’s and despite a year of heavy use only have minor problems. One has occasional gimbal problems and the other loses video signal at short range once it gets warm. But I decided it was time to get a new one and purchased the Phantom 4 Pro. Boy what a disappointment that has been. From the very beginning it had problems. The signal breaks up ever 20 or 30 seconds, even when just sitting on the ground a few feet away. The video is noticeably jittery. And every few flights it gives a gimbal overload warning. Usually powering down and up fixes that by not anymore. Now it won’t go away. So I figured maybe I got a dud? So I bought the new Pro version 2. Hah! Another piece of junk. I’ve had only two flights now. Any time I stop or turn the drone, slowly even, the camera jogs sideways for a second. And it warns me as soon as it gets a few dozen feet away that there is some compass error and I should switch to ATTI mode. I wish I could take both of them back and switch with two new non pro models. These heavier cameras just don’t jive with the gimbals. Beware!

Sorry to here your having problems , the only trouble i have had is the gimble will wobble in a high speed LH turn and the shells suffer stress cracks ( on my 4th p4p+ ) other than that all i can say is wow what an amazing piece of kit
Hope you stick with it and get those problems sorted soon

I too have the gimbal issue but on right hand turns, i put that down to forgetting the gimbal guard on the odd occasion  

With regard to the compass error, usually that is caused by taking off from a surface that contains ferrous metal, often concrete with steel reinforcing bars in it. If you could post a flight log of one of these flights to PhantomHelp: http://www.phantomhelp.com/LogViewer/Upload/ we could examine it for you. Go to the sitem follow the instructions to upload your flight record, then come back here with a link t0 the result and post it in this thread.