I am having and have had the same problem since approximately November 2021. VM contact centre pass me round their teams as quick as they can get rid of me. They have escalated it, sent out an engineer, told me to wait 48 hours, contacted their IT Dept (who advised the numbers I have been trying to dial, are not in service! One of them is my own Irish mobile - Vodafone & sufficiently topped up). There appears to be an inability and lack of willingness to resolve this issue such that I can’t help thinking VM are restricting my use of the service (I have paid for Talk International). I shall soon be ditching VM for a dedicated VOIP provider, Vonage or similar. Suggest you do the same.