Well, I have been having the same problem as you and I certainly have a solution as long as you have another Android device that has Google Play.
Search the net "google" for a program called "Real APK Leecher". Install that on your PC. Open that program and follow the instructions. It is a standalone program linked to the Android Marketplace.
You download the Apps you want through it and copy the files to your tablet and install them. The only downside is you need a PC and another device like an Android phone thats connected to Google Play.
I have read your problem the same i have faced in few days ago and when i was checking the site ranking of my site and some times google perform dance with site because of change in its algorithms.
