Scam phone call

[helzapoppin]

Nearly every day I get a call from  02034760720 when I first answered, it was a 

recorded message about National insurance number, so I have blocked it

on my mobile Now I keep getting notification’s of missed call.

some people say it’s a RAC number which the scammer’s are using.

can’t bt. block this.

[ctrlz]

Unfortunately there's no way of BT blocking a number on your behalf. You've done it the right way, only other thing you could do is deactivate voicemail or block 1571, but both have further ramifications if other people need to leave you a message.