Six wires in outlet box, from 3 different circuits; 4 are hot?
The only way you can get 240 across a back and white wire in america is if one wire is wired to one phase, and the other wire to the other phase (and not the neutral bus bar).  Find the wires in the panel and move the corresponding neutral wires off the breakers and move them over to the neutral bus bar.  No grounds to work with?

Recommend you have an electrician do it unless you know what to test and check o make sure lal is well after the swing is done.  Combining phases on accident I have heard is no bueno.