Hi,
Yes, pts are entitled to one pair of glasses following cataract surgery. That also means that they can get one pair after the right eye is done, and one pair after the left eye is done, if they are done far enough apart to warrant glasses. Pts can go to non par providers as long as they have a supplier number issued by NSC. It sounds like they made your supplier number effective after the service date. When you complete the supplier application it usually takes about 6-8 weeks to process, if everything they need is there. If they have to request any info that will delay the process.
I would recommend that you call DME for your region and ask them what date your supplier number became effective and ask them why it was delayed. If it was something on your end, you probably can't do anything.
Good luck
Michele