Behind the space used to store my washing machine, the floor has separated from the wall. Now my washing machine will not complete the full cycle because the floor sags and washer is not level. Do not think it is a foundation problem. Just not sure should we call for washer repair or a contractor. Have tried to level the washer, but still will not compete a full cycle.

I'd worry more about why that floor is sagging first. Issues like that can get exponentially more expensive fast when ignored.

Is there a basement under that space, with exposed joists? Go look to see if all beams, posts, and joists are solid and attached where they should be.

I'm assuming that you're talking a concrete floor and wall?

The washer should be fine, you just need to find a level floor for it. No need to call a repairman. You need to get the floor level.

The fact that it's separating from the wall, indicates a huge issue. Call a contractor.