Transcend 16GB pen drive write protect error

Hello,
My transcend 16GB pen drive got write protected error in middle of file operation. I was working on linux and having ext4 partition on the pen drive. The file system got corrupted and I lost all the data. I was able to get my pen drive working again using the recovery tool provided by transcend but I could not recover my data.

I am having doubt if 16GB drive a real 16 GB drive or some 12GB drive having some on the fly compression masquerading as 16GB drive?

Reason for my doubts are:
1.) The drive get write protected only when it is more than 70% full. If the drive can't accommodate more data despite on the fly compression it locks itself into write protected state.

2.) The recovery tool is able to get the device out of write protected state but at the loss of data.

Regards,
Jasvant