Fluctuation in your subscribers count is normal. We regularly remove spam subscribers or it's probably viewers unsubscribing and subscribing to your channel normally. Here's more info: https://goo.gl/croiE1 . Hope this helps clarify.
We give careful thought to every YPP application and each one needs to be manually reviewed by our team of specialists. Due to the high applicant volume, it’s taken us awhile to review every channel. We’ve been sharing updates about this here: https://goo.gl/4DGA7r