Not Receiving OTP codes from anyone

[SteveH65]

Just swapped my Pay Monthly sim from an android phone into a new iPhone, everything seemed to be working fine until I needed to receive a OTP code from Amazon. 
It never arrived, same problem with bank and with MyO2

I don't have any blocked numbers and have confirmed that my number is in the correct format for iMessage. Doesnt even work if I turn iMessage off.

Do I need to reset something?

Do I need to tell O2 I have moved from Android to Apple? If so how do I do this?

Thanks for any help

[Cleoriff]

No problem @O2Lisa  (even though you weren't required in the end )

[Sophie_91]

Hi there,
Does anyone has a solution to this problem as I've just spoken with o2 on the phone who have provided no help whatsoever
Thanks

[gmarkj]

Some people have resolved this by removing a spend cap.
Try calling o2 and asking them to increase it to £5.
Some advice on calling and numbers to try in the link below @Sophie_91.
https://community.o2.co.uk/t5/Other-Products-and-Services/Coronavirus-Covid-19-Community-Help-and-Su...