Qualifications can be and will be revoked due to; a substantial period of inactivity regardless of LOA notification, a significant change in the course and SOP of the qualification, incorrect accreditation and lastly, poor performance within an operation exhibiting a requirement of retraining necessary. 

If you feel your qualification(s) has been incorrectly revoked, send a PM to the management tag, explaining which qualification you feel you should maintain and why that's the case.