[ElaineM]

You have received excellent advice from everyone. I just need to add a few suggestions of my own.
Find out what your state laws are regarding health insurance. There must be a state office that overseas those things. Call them and ask for advice.
Find out what the federal laws are regarding health insurance and what and what not an insurance company can do under your circumstances. Find out what you can do legally.
Call your hospital or oncology group and make arrangements for a temporary payment plan just in case you have to go that route.
Consider applying for your state Medicaid plan if all else fails. Low income uninsured working people may qualify under some circumstances.
Make arrangements for your health insurance premiums and rent/mortage to be automatically deducted from your checking account every month just in case you are not able to take care of those things yourself.
All the best to you. Have faith that something will work out for you eventually.