Can you only add one upgrade at a time?

I recently received a bunch of upgrades from Fizz like $2 off internet, $1 off internet, 500mb of data, and 2 x 250 mb of data. I added the $1 off internet and it worked. I tried the others and when I try to apply it all the current upgrades shake on the screen and nothing happens. Can you only add one upgrade per cycle?

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