No longer receiving verification texts from third parties

Since transferring to virgin media a week ago I am not receiving verification texts from third parties on my o2 mobile. I've reached out to both vm and o2 for assistance but vm says there are no problems with my WiFi and I have not managed to contact o2 at all as yet. I think it must be to do with vm WiFi filters (I'm not very techie) but this is a big issue for me as I cannot verify my identity with many organisations i deal with regularly.