iPhone: Silence Unknown Callers not working

I have started getting multiple calls a day from different numbers that ring through when this feature is turned on. I suspect this is because while they are all different (fake) numbers, all have the caller ID of "MEDICARE ASSIST". Thus, they are on my recent calls list. Even if I delete them rapidly, the calls still get through because the simple workaround these scammers have found is to make two calls in rapid succession. This immediately places the call on the recent calls list. Is there any way to not have calls on the recent calls list get through? Because with this exception the feature is nearly useless. If this is not possible I suggest this be added so that these double calls stop coming through. I literally get 10 times more scam calls than actual people calling so this is a real issue. I have to pretty much leave my phone on Do Not Disturb all the time now because of this.