If you do not complete at least 25 Arena Matches on Offense each week, then you will drop a tier at reset. This is written in the Game Help somewhere.

You did not complete 25 matches this week, so fell to Silver 3 from Silver 4.

Then you were attacked, and lost a defensive battle, or even lost an offensive battle, and you dropped the 6-12 points required to bring you from 1600 at the edge of Silver 3, to 1592 or thereabouts, into Silver 2.

Lastly, as I wrote in the other post, I understand being frustrated, but lets not be rude or profane when asking questions here. Thank you. We'll see you when you've sat out your ban. Have a good holiday!