Sorry to hear this DG.
You may already know these things, but I'll bring them up anyway, just in case.
The only thing I can think of is that there are some silicone adhesives that don't bond to cured silicone as well as others.
A general rule I was told by Matt K about one part silicone adhesives, is if the silicone adhesive has a vinegar aroma to it, it will bond to cured silicone, so long as cured silicone is well cleaned with rubbing alcohol, or better yet MEK or acetone, AKA nail polish remover.
One of the best one part silicone adhesives that I know of is Slipoxy. Perhaps give this a try. Just note that is cures very fast. setting in 10 to 15 minutes, coming to a full cure in 1 hour.
The only other thing I can think of is if the silicone feet are made of something else other than silicone, such as TPE, if that is the case, silicone wont adhere to it.