How to reattach the wall cabinet

Seven-foot tall closet next to the entrance has pulled out from all the screws holding it. 2011 Bighorn 3610RE. The screws come thru the wall from the outside and into the 3/4" thick wood sides of the cabinet. The outside finish material sheets were then installed over the screw heads blocking any access to the screw heads. The wall is hollow with a 1/8 thick material covering. The shelf material inside the cabinet is 1/8 thick. I am checking if I can use angle supports from the solid cabinet sides and use expanding hollow wall anchors. I am unable to find any solid framing to attach to. It was a concern to me about the method used to attach this cabinet without any way to access the screw heads.
 
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