Most people who took the EIDL advances where under the impression that there was no interest accruing in the first year, nor the extension. There were just no payments due.
Interest was accruing and now the original payments that were sent are not enough to cover the back interest payments. So, the balance has ballooned up for most people and now you owe interest on the interest.
There is good news, the rate is fixed for the 30 years at 3.75%. The recent run-up of interest rates does not affect this note. You may have noticed that all other business loans you may have seen interest rates climb with lines of credit. I know mine have basically doubled.
Remember if the money is used as intended for the business, it is deductible. If you spent it on personal items be wary of deducting the interest payments. They plan to audit a number of accounts.