I get phone calls from collection agencies all the time. I have no desire to change my phone number since I've had it for so long. Theese guys will call every single weekday just because I know a couple of people who do owe some debts.
You can try to actually call them back and tell these collections agencies that you aren't the person that they are looking for. This can sometimes work, but my experiences have almost always been that they will ignore this and keep calling anyway.
If you are the person who actually owes the debt and the collection call is legitimate, I believe that it is within your right to tell them that you refuse to speak to them on the phone and that any further communication must be done in writing. But honestly, good luck at that because it can be difficult to get collections agencies to actually give up.
In the end, it may be just easier to ignore them, especially if you don't want to change your number. Most phone these days allow you to send all calls from a specified phone number directly to voicemail. In addition, there are apps out there that can answer the call and hang up on them, but my experiences have been that all of these apps still allow these calls to come through for at least one ring before answering and disconnecting.
The problem is if you actually owe, changing the phone number may not always stop these calls. After you've used a phone number for a while, the collecitions agencies may find out your new number eventually.
