Can only afford interest on HELOC. 11.5% now!. Can't refi into HEL bec. of low appraisal. Any alternatives?

$34,000 interest-only balance hasn't budged in two years thanks to Federal Reserve raising rates. Can only afford to pay the interest, not the principal. Know that a credit card transfer would eliminate the tax deduction, but see few alternatives. Tried a refi application, but appraisal shows loan is underwater because of falling home prices in the area -- that means not enough equity to cover the balance on the Heloc!