In 2008 Roy Bros. Propane in Ashburnham, MA, installed a propane tank for my gas stove. The contract made no mention of a MUC. Roy Bros. was later taken over by Osterman.
Three or four years ago they sent me a bill for MUC, which I reported to the Better Business Bureau, which contacted Roy Bros. I had no problem for 3 years.
Last year Osterman did it again and I filed a complaint with the consumer affairs section of the MA Attorney General's office. That was effective. I changed propane suppliers two weeks ago and Osterman waived the MUC.
If your contract with Osterman (or whoever) does not mention a MUC, do as I did. You should have good results.
(I'm still waiting for a rebate on unused propane, no surprise.)
Reason of review: see my filing.
Preferred solution: rebate on unused propane.