Zepto scam?

So recently Zepto is trying this scheme in which they add some money (usually 50₹) to your wallet and say it is only valid for the next order. But when you try to spend it it shows “Zepto wallet currently unavailable”. This keeps on happening where they expire the money and after two days it credits the same money which again turns out to be ‘unavailable’. Why even credit the money if they won’t let us use it??