05' Sprinter van remotestart

I have customer that I put a remotestart on his 05' Sprinter van.It has a program key that I am using the one the boxes that you put the key in it.Well it worked fine for 2-3 days then stopped working. He brought it back and I tracked it down to the ring from the key box. To get it back to working all I have to do is remove the panel under the steering column and just move the it a 1/16"-1/8" for it to read the key.Has anyone had this problem with any of these vans or any Mercedes? Any ideals on how to fix this problem?

The ring would have to be around the key barell and it is also best to tape it good so the ring does not move at all.