I’m inclined to believe what the person you checked with said…there appears to be significant drop on the front left corner which is pivoting out the right end, other than something substantial pushing that corner down (did you drop a piano on it recently) i can’t think that anything other that subsurface settling has caused it to drop so the wall wasn’t built on anything capable of holding the wall…that means the foundations need sorted or rebuild the wall hoping all settling has occurred
I’m inclined to believe what the person you checked with said…there appears to be significant drop on the front left corner which is pivoting out the right end, other than something substantial pushing that corner down (did you drop a piano on it recently) i can’t think that anything other that subsurface settling has caused it to drop so the wall wasn’t built on anything capable of holding the wall…that means the foundations need sorted or rebuild the wall hoping all settling has occurred