I had my Full and final offer accepted and I've paid the amount to the IVA company in question they have advised that this is the end of my commitment to the IVA now and that the case go into final process and my certificate will with me in due course. The question am I allowed to know build my credit status back up or do I have to wait for the certificate
You won't be able to do anything until you have that certificate and are removed from the Insolvency Register, and, even then, things are limited until the 6th anniversary of your start date.