Blocking phone numbers on nougat

[MyUsernameRox]

It allows us to block individual numbers and also has a function that says digit blocking. Initially I thought this meant you can block area codes and /or prefixes, which would have been a godsend because I'm always getting spam calls from numbers that start with my area code and prefix.

However, this hasn't been the case. I have tried the following combinations in the digit blocker and none of them work.

1714
714
1714589
714589

Any advice? Or am I completely misunderstanding the function of the block by digit? I very much doubt that I am.