I didn't know where to put this.

I sometimes phone a non-publicly advertised 0800 number for a business.

However at some time in the past I discovered that it was not possible to dial this number for a particular reason because I got the recorded Telecom man saying "The number you have called is not available from your location".

The usual message that you get when you phone an 0800 from a cellphone and it is barred because it is a cell.

But the strange thing is, that I can get through on my 021 cellphone, but couldn't not get through on my 022 when I tried today.

I tried my landline - also not possible with the same recorded message.

All 3 phones are sending Caller ID through as normal.

Any plausible explaination for all of this?