ATHENS — The ads come close to suggesting that the apocalypse could be just around the corner if Greeks make the wrong choice in a referendum on Sunday.

Against a blue background, a cheery cartoon rendering of an A.T.M. appears and an announcer asks: Will there be cash on Monday?

A big red “X” crosses it out. Will there be gasoline? Will there be medicine? Will pensions be paid? As the ad continues, a dozen such questions are answered with a resounding “no,” before the tagline appears urging voters to say yes in Sunday’s referendum.

“Now that we know how many nos a no can bring,” the voice-over says, “On Sunday, we say yes.”

In the referendum, Greeks will be asked to decide whether to vote yes to accepting a bailout package that would keep Greece solvent and in the eurozone — but impose more taxes and pension cutbacks — or to vote no and demand a better deal or, possibly, be kicked out of the eurozone.