Your "stabilizer" jacks should be frame mounted, not floor mounted and from the quotation marks, you should glean that they are stabilizing jacks, not leveling jacks. They were never designed to lift your trailer, even if attached to the frame, they shouldn't be used to lift the trailer. They are used merely to "stabilize" the rig to hold motion down.
To level your trailer, use plastic lego blocks (my favorite) or wood blocks to put under the tires on the low side. Once level side to side, then use the tongue jack to level front to back. Once the rig is level, then you put the "stab" (stabilizer) jacks down just snug enough to keep the trailer reasonably stable; never torque them enough to actually lift your trailer.
I can't imagine who or why someone installed your jacks on the floor and not the frame; I've seen a lot of trailers, and even ones that are difficult to find the space, have the jacks attached to the metal frame (that's where they belong). My 210WBS was crowded, front and rear, and the jacks were anchored kitty cornered across the frame corners, but, on the frame, not the floor.
First thing you need to do is to get them removed and remounted to the frame where they belong to keep from doing any more damage to the floor to frame mounting. Next step, to repair the damage already done... If it were me, I'd get one of those flat, wide wrecking bars and wedge it in between the floor and frame and use it to spread the loose area. Once you have the gap open, using a caulk gun, squirt some weatherproof construction adhesive into the gap and then pull the wrecking bar out letting the floor's weight serve as a "clamp" as the glue sets. With the jacks properly mounted to the frame, that should hold the unit's floor down well enough and the jack's stress point will be under the frame supporting the entire assembly.
My 2 cents, your mileage may vary...
2 Cats; J-Lo and Ragamuffin :R
2014 Thor Tuscany 40RX DP
2011 Ram 2500 Longhorn CTD HO
2011 Keystone Cougar 318SAB (now gone)
2008 FunFinder X 210WBS (Sadly gone)