Boric Acid is often used to treat or eradicate bedbugs. However, it doesn't work particularly well. It has to be ingested to kill them, but they don't necessarily consume it. There would need to be a bait that they can ingest that contains boric acid. Unfortunately, people are the bait that they respond to. Cockroaches, on the other hand, ingest it, because they clean themselves. Therefore, it gets ingested in that way.
You should avoid any treatment method that heavily relies upon Boric Acid for treatment or eradication. If exterminators inform you that this is their primary tool, then you should consider finding another company to treat your bedbugs.