4G not working

[cbarnes1186]

I’m wondering if anyone can help please. 
I have a iPhone 13 and it won’t connect to 4G. Obviously Vodafone are rolling out the 3G network (thinking about it, my phone hasn’t been able to connect to 4G for the past year and I’ve been in places where 4G&5G is covered!) which doesn’t help when needing to use my phone via internet when out of a wifi zone. 
I did have a contract that ended in December but due to payments for my device failing to come out I’ve now racked up a huge bill for that (which I’m gutted about) would this be a problem as to why I can’t connect to 4G?  I’ve been in store to try and make payments towards the device plan and they’ve said to ring Vodafone customer service, but when I’ve done that they’ve told me I have to go in store to arrange payments and I feel like I’m going round in circles. 

[Effie]

Hey @cbarnes1186 I hope you are well. I can certainly appreciate how concerning this must be. There are a number of reasons why this is happening but without looking at your account and running some checks on your number and SIM, we wouldn't be able to say for sure what the reason actually is. As we have no account access on the Forum, please pop the Social Media Team a message here so they can check this all out and get you back up and running. 

[cbarnes1186]

Hi I rang Vodafone this morning and they told me I had to pop into a store and pick up a new sim as it sounds like my SIM card only allows 3G signal. 

[Effie]

Thanks for getting back to me @cbarnes1186 That's very strange as all SIMs are 4G and 5G compatible. If possible can you please drop the Social Media Team a message so they can double check this for you as the information you've been given doesn't seem right and I don't want you to go all the way to the store if it's an issue we can fix from our side. 

[cbarnes1186]

I was told my sim is an old sim and that I need to update it. 

[Effie]

If you're happy to go into store to get a new one that's absolutely fine @cbarnes1186 just remember to tell them that it is a replacement SIM for your current one and ask them to activate it with your current number and plan.