Can't receive unknown numbers

[Mydad]

My dad has an old Sony flip phone not a smart phone. He bought it from o2 along with a sim, pay monthly about a year ago.
He cannot receive calls from unknown numbers including doctors and hospital appointments. Please help. Thank you.

[Cleoriff]

@Mydad 

He may need a new sim in which case popping instore is the quickest way.

If that doesn't cure the problem then he probably needs a new phone.

There are good deals to be had in the O2 shop for refurbished phones or Tesco, Amazon etc.

[MI5]

@Mydad 

Check in call settings to see if "Block unknown callers" is ticked.

[LukasB]

Hey @Mydad did you get this sorted out or are you still having trouble with this?

[Mydad]

One hour and fifty minutes on Web chat with o2. Tried the codes they sent me but still no joy. Forty minutes on a call to o2, again codes but problem not solved.
Took phone to o2 shop, Connswater, Belfast. Guys couldn't touch my phone but talked me through the settings to lift the bar. They googled the model and advised as, like me, they couldn't see obvious settings to change. Four minutes and I was sorted and on my way.
A big thank you to everyone who replied to my post.

[Cleoriff]

You're very welcome @Mydad 

[MI5]

You're most welcome.
Glad you're sorted.