Typically, work can not be started until the bond is posted to avoid those types of situations. However, that is not to say it doesn't happen from time to time.
We have had many phone calls over the years of
contractors trying to get a bond they do not qualify for after work is well under way. Sometimes they qualify, but
bonding companies do not want to touch contracts that needed to be bonded mid-way, as they usually suspect something is already wrong and the obligee is simply requesting the bond to pay out on their problem.
In other words, if you have a bond requirement, make sure you fullfil it prior to starting any work!
Also, contact your attorney to see what the next step is for you.