Pitney Bowes PB refuses to refund remaining postage after saying they would Bartlet Tennessee

Pitney Bowes refuses to refund the remaining postage in my Mailstation as they promised to.  i was told that I could either print out postage slips or they would refund the remaining balance as long as it was more than $25.

The told me to remove the postage from the machine and ship it back, which i did.  After 2 months, they said they would not refund the postage because it was  free postage and was an incentive to keep the machine.  I told her I was told they would refund the remaining balance, and that I had also put in postage on my own other than the free postage.  She said the post office owns the postage and they couldn't do anytihg aobut it, but she did offer to refund the last month's rental of the machine of $29.99---which I guess is better than nothing.  But--what a bunch of thieves!