I am thinking they stopped paying thinking UMS would be public by now, time got in the way, suppliers are suing, I assume they were thinking with the revenues and this done pps would be way higher, giving them leverage or at least be able to pay with shares, classic robbing Peter to pay Paul scenario.
I am thinking they didn't stop paying because the are broke, but refocused that money on getting this process completed. As usual with that type of situation it must be completed quickly or everything will catch up...