It is a good idea to get quotations from a few hacking contractors to compare the rates that you are getting and the services that they provide.
Also, if you engage a third party, the cost of hacking is increased significantly. On the other hand, liaising directly with a contractor that can handle the entire process would mean that they are able to regulate the quality of service and provide you with the best prices.
Through requesting for quotations and interacting with various contractors, you would have a better idea of their work ethic and ease of communication. It would be ideal to get someone whom you can trust to provide constant updates of the situation.
It is important that only non-load bearing walls are being hacked, as mistakenly removing a load bearing wall can affect the stability and foundation of a building and cause complications.
Experienced contractors will be able to get the job done right, well and quickly.