Need more than 25 phone block spaces

Hello, 

How do I obtain more space to add more than the 25 numbers I already have blocked.  I keep getting these annoying 800 service numbers from multiple lines and leaving voice mail  telling me that I owe $499 which I don't.  I've tried deleting other numbers to add the 800 numbers, but then I get calls from the other numbers that I have deleted. I do have robo calls blocked

Please help  If there is a device that I can add and/or buy please let me know.