Issue with Tac Dev Basepad

[Defender]

I have a macro 17 round magazine that I installed a Tactical Development XMA plus 2  base pad on a while back and have kept it as a backup mag.  Yesterday I went to take rounds out and discovered that the spring was stuck all the way compressed and the rounds all just shook out.  As I shook it, the spring decompressed and sent the follower part way thru the top of the mag.  I was able to get the follower out but the spring is still stuck in the mag.  I tried disassembling the floor plate but while I was able to get the part off that is secured by a set screw, I couldn’t get the base pad off.  I asked tacdev on their website but haven’t gotten an answer.  Anyone have any ideas on how to get the floor plate off and also why this happened?  Whenever Sig releases their Fuse 21 round mag for public consumption I will certainly buy a couple.  The reason I did this mod was I have a tacdev regular base pad and I really like it and the way it feels in the hand as well as it looks good.  When I decided to get another one, the plus two looked appealing and I said why not.

Edited September 11 by Defender
Added photos