Clyde, I moved your post to its own thread and in a more appropriate section where you might get better help.
From your description, it sounds like the pump motor is working properly and you have sufficient power, so that just leaves hydraulic pressure as the problem.
So, is there fluid in the hydraulic reservoir? With the top down, it should be within 1" of the top of that tank. You can check this by making a "dipstick" of sorts out of wire that is bent so that you can get it into the top of the tank with the top of the camper down.
Next, if you have fluid in the tank, is the manual lowering valve at the pump possibly open? If it is, the top will not go up since the system cannot develop pressure.
If neither of these is the problem, you might have a leak. Is there any hydraulic fluid on the ground, either under the pump or, more likely, under the ram back midway under the trailer near where the axles are mounted. If you have a leak, the system will again not hold pressure and you will have to get the hydraulic system rebuilt. This is something that can be done by most any shop that does hydraulic work, so it can be fixed.
Possibly, someone else will have other ideas. Don't give up too soon.
- Jack