Can I block a series of numbers: 866-563-XXXX?

I've been getting bombarded with phone calls that get through Nomorobo, anonymous call blocking, etc... They show up on caller ID (and voice mail) as "800-Service." They get through to voice mail every time. Yesterday, I had 10 voice messages from these numbers in a span of a few hours. I've already had three this morning in 20 minutes.

However, I only get 25 manually entered number blocks, and these were already filled up years ago. I need to block every call coming in from 866-563-XXXX. I called Xfinity and the person only got to me to where I already was. She thought I could do a series by using *60 through the phone, but it's no different than number blocking online.

I attached a screen shot to the voice mail page online from two of the three from this morning. There was another one in between, but I answered it.

Is there a way to do this?