Your description of the bridge problem seems to indicate that the guitar top may have acquired a rather permanent warp. The string tension alone can easily cause a change in the wood, but condititions of dampness and drying can facilitate the process. Correction of the problem might be possible without removing the sounding board and bracing if the braces have come unglued, but if the problem is extensive, it may be easier to remove the sounding, reposition the wood and reglue the bracing. Before you undertake the repair, consider the value of the guitar against buying a new instrument. It is, after all a manufactured instrument. Extensive luthier work is expensive and generally only justified on hand made instruments or instruments with some intrinsic historical or personal value. Limited repairs may get you a working instrument, but the wood might easily return to its current bad position. It has a new memory, as I assume you have loosened the strings and found that the bridge does not return to the correct position. Consult a luthier who can give you some prices and a degree of assurance about what needs to be done and whether the repair can be guaranteed.
Alternately, you might be able to have a working instrument by adjusting the neck angle to bring the action back down to a playable height. Does your instrument come with a neck rod? If so, change the neck position. If not, detaching, shimming and regluing a neck is also expensive.