If your only late payment in the past 6 years was a 30-day late on this HELOC then you should probably be fine to refinance. Yes a mortgage late payment in the past 12 months does hurt (your score as well as some underwriters won't be very comfortable with it) but it's certainly possible to still get approved for a cash out refinance. Your lender actually said that the late payment will cause your loan to be declined? If so, then I'd check around with some other lenders as not all lenders have that guideline.
hopefully they don't pull your report again now that the underwriters already have it. I think worst case you would just have to write a letter explaining it. You should be fine.
Any time that a new mortgage payment is due during the mortgage process it needs to be verified that it's been paid/hasn't gone 30 days late... or underwriting needs to factor that into the loan approval.
After an extra week, a loan extension and a lot of hard work by my lender, I closed on my refinance! The late payment still hasn't reported. I can't believe I messed up, but at least my house will be paid off in 15 years. THanks everyone.
That's Great I'm so happy it all worked out and thanks for updating us all