It's called Vendor Lock-in. Basically means once you rely on their software, you either:
a. Suck it up and pay them Extortion, er, I mean Maintenance & Support for the rest of your life
b. Pay them a shed load of money to be able to extract YOUR data in a transferable format
c. Not sure I can think of a c TBH
And when they can't even be bothered to follow their own "standards" so later versions of their own software have issues reading data from an old version, you are stuck in the situation you are now.