What aggravated me last night was a took an LA7 and once it got over 1000feet it decided to go nose up, and roll left. No amount of trim could get it to stop.
Is it possible it's a joystick problem?
There are two types of trim in AH. Auto Combat Trim, and Manual trim.
The easiest trim option available is to simply make sure the Auto trim is enabled, which you do on the clipboard under Options/Preferences/Flight. Make sure the box for Auto Combat Trim is checked. (Since you're there, I'd make sure the stall limiter box is UN-checked as well, but that's a different subject...). In flight, there should be a small light showing for "Combat Trim" on the instrument panel.
Does the plane fly fine like that? If so, it probably isn't a joystick problem.
There's no reason 1000ft would matter when it comes to trim, and the same can be said for the joystick. Rolling left could be due to engine torque, and a stall. How fast were you flying at that point?
If any of this helps, great! If not, maybe you can film what's happening and post it here, so we can see?
Are you new to the game, or pretty experienced?
Manual trim doesn't amount to subtle changes, but they're not drastic instantaneous changes either. If your joystick is fine, and Combat Trim works, then I'd suspect a mapping issue with your Manual trim set-up. What type of joystick, and how are you mapping them? To the stick or throttle? To the keyboard? To a button or to a dial?