Lyra Delos - Dirt Build up on the cantilever

Hi folks, hoping that someone (Jonathan ? :-) may be able to shed some lights on my problem. I am a long time user of Lyra cartridges and love their sound. I bought my first Argo i back in 2008 from Acoustic Sounds. that cartridge has served me well to this date. Then on Oct 2014 I decided to buy the Delos since I read excellent reviews of it and its comparison to the Argo i. I bought my Delos from HiFi Heaven. for the first couple of years the sound was excellent and all that I expected. then around 3 mounters ago i noticed mistracking  on some of the records. I have to mention that with both the Argo i & the Delos I re-check the settings once a year (these cartridges are very sensitive to correct settings). Also its worth a mention that I am extremely finicky with cleanliness of my records, the treatable set up and care of the cartridges. I never play a side before throughly cleaning the record and alway clean the stylus with the SPT liquid and brush only.
Then around a month go one day the arm just slide right across the record.
I immediately contacted HiFi Heaven and they said that they are no longer a Lyra dealer and suggested i contact the distributor, Audioquest. I did this and they offered to send my cartridge back to Lyra for examination and review. This they did. In the meantime I put back my Argo i and started enjoying music again. before doing that I examined the stylus and cantilever of the Argoi by a X60 magnifying glass and everything was perfect. this cartridge is currently installed on my Clearaudio Performance turntable.

The yesterday I received the result of Lyra examining my Delos which was:
 "Lyra have informed us that this cartridge is not eligible for service under warranty. Due to a build up of dirt, the cantilever is unable to move. An attempt to repair this would result in damage to the cartridge"

......and here is my frustration and confusion.  I have no doubt that Lyra have done a through job in the examination of my cartridge. However, I know that it is impossible for the dirt build up to be caused by me and my use. The Argo i after 9 years of service in my system, playing my records and being cared for by myself at all times is still performing well and the stylus and the cantilever are shinny and clean.

The Delos has had the same treatment and been in the same system and played the same records for much lesser of time (less than 500 hours in under 3 years).

To be honest I feel like I am being accused of something that I have not done. How could I cause such a level of dirt build up to prevent the movement of the cantilever on one cartridge and not the other one.

Any thoughts on this or similar circumstances will be appreciated.