Premiere Credit of North America Debt paid in full, yet Premiere Credit continues to garnish bank account Indianapolis Indiana

We owed the state of Indiana taxes on our  2011 tax return.  Due to being unemployed we made arrangements to pay the amount over several months.  We paid every month $116.01 to the state ending in December.  In March, 2013 we get a letter from our credit union stating that our account has been garnished for $116.01 for income tax owed.  My husband calls the yahoos at Premiere Credit and says it has been paid off already.  They indicated that we owed one more payment of $116.01.  So he paid it over the phone by credit card and was assured the lien would be removed from our bank account.  It was not and earlier this month, May 2013, the credit union paid them another $116.01.  Then on May 23, we got another notice from the credit union that the account was being garnished for $116.01.  Then on May 24, we got a letter from Premiere Credit demanding payment for this outstanding balance of $116.01 that has now been paid three times and I assume will be paid again in 60 days as that is what the terms of this garnishment state.  Obviously this is some kind of a scam they run.  I have been hit twice now with a $20 garnishment fee against my account that I am sure I will never recover.  Of course the letter from Premiere states that we are to contact them and not the State of Indiana regarding this situation.  We will be contacting the state to ask what their records show we owe because this is bogus.  We made arrangements to pay monthly to the state and made those payments each month.  It is obviously shoddy record keeping on part of the state and even shoddier record keeping by Premiere.  Premiere claims they contacted us in July, 2012, another lie on their part.  We received nothing from them.  If they contacted us in July, why did they wait 9 months to collect?  And if the account was really turned over to them, then why did the state of Indiana agree to take monthly payments and why did they continue to accept those payments for 6 months after they supposedly turned it over to collection?