I don't have any first-hand knowledge about unpaid bills. But if the airport is being impatient after having Via for only a few months, then I'd guess that Via isn't talking to them. THAT's a mistake. Not fun to have those discussions, but it's a part of doing business.
Which brings me to a broader point. Airlines going through big growth spurts (think Via, PenAir, Boutique, CommutAir, and others) very frequently find that not all parts of the business get their act together equally rapidly. Or as fast as they need to. In most cases, they're trying but executive time , atttention and perhaps cashflow are split between too many needs. Those times are often hardest for the HR people.
If you believe in them, cut them some slack and work with them to solve the problems. If not, go elsewhere so you can be happier and have your (perhaps unreasonable) expectations fulfilled.