Dealing with corrupt owners in an HOA (Panama City)

I am on the board of a small condo project where the owners of a third of the units have refused to pay there maintenance fees and power bills for over a year. Over $30,000 is owed by these "morosos". The location of the condo is over 5 hours from Panama City. We need to get them to pay and pay quickly. We have been dealing with this for a couple years and are getting nowhere. It is hard to find a reliable English speaking lawyer that will take this on and give us the correct interpretation of Panamanian law on this issue. Any suggestions?