That lawyer should have notified you first, then you could have passed them on to your lawyer. These arrangements are not a blanket thing, they are typically on a per-case basis. And your lawyer likely should have contacted you to get your agreement that they were going to represent you in this matter. Which likely they did only you didn't realize that that was what was happening. If my lawyer started to invoice me for a matter that I did not refer to them I would tell them to go pound sand, lawyers or not. So beware of accidentally agreeing that they could represent you if they notified you.