Columbia Construction Services and David Schatzberg and Mark Provenzano are crooks. This group of crooks failed to pay us over $25, 000 after we performed subcontract work for them. It took us over 6 months to get over $40, 000 that they owed us and we had to get that money directly from the owner of the job. These guys are total crooks. They stopped answering the phone and returning phone calls when someone did answer the phone. Beware all subcontractors, this company is a bunch of crooks, they will keep your money. They had many liens filed against them in Florida and on the same job.