Lap band to VSG in Mexico

I just received news from my Baractric Clinic that my pre-authorization was declined for a revision from lap band to VSG.  I can't afford to self-pay at my clinic ($20,000).  I sent an email for information to Dr. Alvarez in Mexico and heard back that I would have to wait 5 months after my band was removed to have the sleeve.  If you had a revision in Mexico, did you run into this problem, or is it just Dr. Alvarez's policy.

Also, if anyone has information on Dr. Umbach in Vegas for a revision let me know how that worked and the cost.

Thanks!

 When I had my surgery in January, there was a lady who had a band to vsg revision the same day with Dr. Aceves. I am not sure on her particular situation, but it is worth contacting them.