Tearing My Hair Out

I just don't know how to get a response from Medshield. Still trying to sort out an issue that started in 2014. Authorisations given but answers given include: Practice doesn't exist, Authorisation required (number submitted), Wrong code (orthodontist says it is the only one), Paid out of savings instead of enhanced dentistry. Bounced from operators to DENIS and back again. DENIS supervisors to phone back and never do. Impossible to get hold of a supervisor from the call centre but the call centre is the only number you can dial.