[asterisk-users] Just got defrauded - how do I block calls which contain a dash (RegEx noob question)

[Markus]

Hi list,

I'm using Asterisk2Billing (v2.0.16) and it appears to have an annoying 
bug. When there are rates for e.g. 44 (UK landline) and 44870 (UK 
premium) and a fraudster manages to somehow dial 44-870 instead of 44870 
the rate for 44 will match, not the one for 44870.

So, I would like to block all calls on a dialplan level that contain a 
dash. -44, 4-4, 44-, 44---, -, ---, just everything with a friggin' dash.

My noob-ish try:

exten => _-.,1,NoOp(Blocking dash)
exten => _-.,n,Hangup

Doesn't work.

On https://wiki.asterisk.org/wiki/display/AST/Pattern+Matching I found:

"The dash (-) character is ignored in extensions and patterns except 
when it is used in a pattern to specify a range in a character set. It 
has no effect in matching or sorting extensions."

How do I do it right?

Thank you!
Markus