So I emailed the Insanely Great folk and asked if they could send me a new suction cup. I received this message from Insanely Great Products co-founder, Richard:
He then proceeded to send me not just one suction cup, but two! Plus one of these for my trouble:I'm also not sure if the missing suction cup is on your end or ours but I'll send you a replacement by Priority Mail in the morning.If it's our error, please accept my apologies. I appreciate your patience and we'll get it resolved as soon as we can.Merry Christmas and Happy New Year.