New customer can send but not receive after number port

[Paul-7]

Since my number was ported last week, I can make calls and send SMS, but incoming calls and texts from most people are not being received. However, when O2 customer services call me, it comes through.

I think what is happening is that calls from some other networks (e.g. vodafone) are routing to my old provider (lebara) and they are getting my old voicemail. It's like Lebara haven't completed their side of the port fully.

So far, O2 customer services have been useless. At first they said give it 24 hours for the port to complete. Then after 24 hours they said give it 3 days. Now they seem clueless.

Things I've tried:

Full network reset on my phone (iphone 13)

Phone restart

Putting my sim in another phone

None of this helped.

I put my old sim in another phone  and then started receiving texts and calls but couldn't make any calls or send texts from that phone.

Anyone understand the technicalities well enough to suggest where the problem might be?

[MI5 · Accepted solution]

@Paul-7 

It's a split port and sounds like lebara haven't updated their call routing files correctly.

I suggest you start with them but also keep on to O2 to check things at their end.