Have you always been with BT , or did you move to BT from someone else , if you were with someone else how did BT migrate your service ?
If other providers cannot or will not migrate your connection, you could always ask them to provide a new connection ( so two connections into the property ) and then simply cease your BT service once the new service is in and working , obviously this will be a little more expensive paying for 2 services for a short period , but would get the job done , this obviously wouldn’t be any good if you want or need to keep your existing landline phone number,
If you can survive with no landline for a short while ( and just use a mobile for example) , just cease BT , then order with someone else once the BT service is ‘switched off’.
If there is a problem migrating , then at the very least , you need to ask the ‘new’ provider what the issue is , because at the moment the explanation you have been given is way too vague to be of any use, bluntly if you want a new provider and they can’t or won’t migrate you , then that’s not really the losing providers problem, with one possible exception, if they tell you the actual reason , it may be something your current provider can resolve, but unless the new provider tell you the reason for being unable to migrate you , you cannot ask BT to check .
