Why do i have to cancel and apply when i should be migrating!

Does anyone know how the migration works the fiber provider says i just need to migrate my line i'm moving in the same complex and my Afrihost account is linked to the Bdcom which moves with me to new unit all i need is a line. I don't understand why i have to cancel and apply for a new line i was with Mweb 13 years before this, moved twice and never and this lack of product knowledge or service once with them!