Private is around 280 and federal 250
That's $530 a month, not $700. So you are right around $250 short each month of making those payments. Can you pick up extra work, drive for Uber, cut out any other debt?
Use the calculators.
Remember, IBR is for federal loans. You likely will not see any change from the Standard Repayment plan for your providate loans.
Have you tried to consolidate the loans so that you're only paying one note? I would try that first and then ask for either a deferment or a forbearance while you get your affairs in order.