Do you live in a very damp area? If not get your money back from those ‘professionals’. Then go to a real professional and after that get your wood sealed. Or just get your wood sealed. I believe that is what they do in damp areas. You could also replace all wood parts with metal. I can’t think of any other solutions, sorry.
Have you looked into this product? We are VERY wary of pest control companies after a bad experience several years ago. So always get real good references before letting anyone come treat your home. Check out this link I just found: http://www.epestsupply.com/questions.htm Good luck. ;)