PMI and HARP refinance

i and my husband have a mortgage on our home from 2008. my husband lost his job in 2010 which sent us into a tail spin financially but all the while we have managed to keep our payments in full and on time. we tried to obtain a modification through our lender, bank of america. they took 2 years only to have them tell us that because all payment were made on time that there is no way we could qualify. after that was over i started calling around just trying to find a refinance option. of course the value of the home is lower than it was when we purchased it and i don't even know exactly what the value even is. i contacted bofa about a refinance and their closing costs are so astronomical that i started looking elsewhere. i found a couple of real promising places with great rates and costs but when we got more into the process we got turned away because of our pmi. something about because we still owe so much on it that they couldn't do a refinance? he told me that no lender other than our current lender would be able to do the refinance because of this. could someone explain this to me? does this appear to be true? and why would our current lender be the only one that could? because of the harp program and what appears to be a very small "under water'ness" of the loan, no one seemed to feel that would be a problem but now the pmi is what is gonna force me to have to deal with that horrid, horrid lending monster known as bank of america!!! any help would be greatly appreciated. thanks guys!!!