If you have an iPhone as your mobile device, you can set up a foolproof filter for pretty much all Robocalls, unwanted solicitations, or anything else that bothers you with multiple calls on your mobile phone.
The first step is to create a Voicemail Greeting that lets people know that they have to introduce themselves with their numbers first, and then once they exist in your Contact List, then your phone will ring and you might answer it. If your callers don’t know, then they will never get through.
The second step is to make sure your Contact List in your iPhone is as up-to-date as you can make it. Trim out any junk, do your best to de-dupe the list, get it so it is nice and tidy.
Third step is to go into Settings, then to Do Not Disturb settings, Turn Do Not Disturb ON, set Schedule if you want it off, although I just leave my phone on DND permanently. Silence Always, and in the Phone section, “Allow Calls From” and set that to “All Contacts”. Turn Repeated Calls off, and any other setting is your personal preference.
When inbound calls arrive, they will be checked via their Caller ID presentation with your Contact List. If they don’t know which number will match in your Contact List, then your phone will never ring. It will obviously ring for the caller, until they arrive in Voicemail, and then they leave a message introducing themselves, which is after all, a civilized way of using these devices. If you met someone IRL, then you’d have to create a contact for them in order for them to ring your iPhone.
If you have any other iOS device, like an iPad, you should configure that the same way as your iPhone so when it is connected over Wifi it doesn’t ring the way you don’t want it to.
After that, you won’t get any more inbound calls unless they are from your Contact List. No fuss, no muss.