Can you provide the exact link/page you used? I’m trying and I have no problem with the 3 sets of stacks (bottom of pager). But, you are right the “bundle” does seem to not be addable. I’m not positive but this may not be an item anymore (i.e. it may have been removed awhile ago).
But see attached. I can get the 3 together for a good price. It’s only about $9 more than you thought you’d spend. I’m sure if there’s an error (beyond the bundle being taken off the market) that Joe will reimburse you the difference: after Thanksgiving Day!