Welcome to Vodafone Community
I'd suggest to contact the Vodafone Social Media Teams via Contact-us-for-account-specific-queries.
They have full account access @SalfordAl
I'd suggest to contact them via Twitter and link back to your thread here including your forum username so your not having to repeat yourself.
As this involves an outstanding debt and debt collection agencies have been involved I'd suggest to also check your Credit File to see if anything negative has been added.
If it has then the same team have a dedicated Credit File Specialist Team who can investigate.
I wish you all the best with this situation.
🌈 Stay Safe & Stay Alert. 🌈
Current Phone > Samsung Note 20 5G - SM9860 Snapdragon.
Samsung One Ui 2.5 / Android 10.