My husband and I have been separated for awhile now. I live at a totally different address. Every year he files Married Filing Separate and I file head of household because I take care of my disabled brother and his child. A few months ago, I received a letter from the MS department of revenue stating that I can not file head of household and that I should have filed Married filing separate and that I owe my state tax refund back. Could someone please explain this to me?