Switch from Monthly to PAYG - No Calls/Messages Being Received!

[Laz26]

Hi O2 Community,

I switched from Pay Monthly to PAYG on Monday, July 28, 2025.

At an O2 store in the UK I was told of the process to follow. I also called up support to validate this.

I made it clear I move a lot between UK, Bulgaria and other EU countries. Keeping my old number is a must.

I bought a £10 PAYG SIM (8GB data, unlimited mins/texts) and started the migration process over the phone with O2 support.

I left for Bulgaria shortly after, and since then, I've faced ongoing issues:

• Calls: Initially couldn’t make/receive calls. Switching to different networks on settings allowed one call, but subsequent attempts failed ("call failed"). Incoming calls ring then hang up or go to voicemail. Tried Yettel and A1 with similar results, one call works, then fails.
• Texts: Can send one SMS per network switch (e.g. Vivacom to Yettel), but the second fails ("Not Delivered"). Receiving texts works intermittently.
• Data: Works fine on all networks (Vivacom, Yettel, A1).
• Short Codes: 4444, 2202, 4445 don’t work abroad (expected, but +44 844 809 0202 also unreliable).
• Account: My O2 app shows the bundle as active. Support added a £20 bundle (unneeded for EU roaming) and has been unhelpful after 7+ calls.

Troubleshooting Done:

• Manually selected networks (Vivacom best so far).
• Reset network settings (no change).
• Checked APN 
• Dialed ##5007672# 
• Restarted phone, toggled Airplane Mode, tested 3G/4G.
• They said migration was successful
• Added sim to other phone
• Plus lots more

I have logged a complaint to get some help, as all supports agents have not been able to do a thing. However, want to see if the community is aware of this, and has a solution as cannot wait any more.

Frustrated after a week - please advise! 

Thanks,

[MI5]

@Laz26 

As you have made a complaint now you will not get support from any other channel as a complaint supersedes all other.

You will need to wait for a response from them.

Guide: How to find help & contact O2 

[Enlli]

As far as Yetel and A1 in Serbia is concerned both have closed down their 3G networks 

As O2 PAYG does not presently allow calls over 4G but falls back to 3G, this may cause call problems. Try locking the phone to 2G, but no guarantees.

Technically text should work but it seems some networks are blanket restricting phones that don't have 4G calling on their network 

If that is the case there is little O2 can do

[omaghlad30]

Same issues exactly

currently in Ireland where 3G networks are active and problems just as bad as europe

complaint logged. No resolution 

[Enlli]

@omaghlad30 Both Vodafone and Three have closed 3G in the republic, that will include MNVO networks that piggyback on their networks 

No idea what is left of 3G over there.

Nothing we can do here apart from advising changing network.