why can't I buy premium using paypal even though I have paypal balance, when I click to buy using paypal there is no paypal balance option, there is only paypal asking for my credit card
Best place to ask payment related questions is email@example.com
But considering how this is a fairly broad question: we have no way of configuring what sort of payment options paypal itself offers during the purchase process - nor any insight as to why something may or may not be available. I can only speculate - but it possibly has to with the currency type you have in your balance? Depending on where you live, payment may be conducted directly in USD and Paypal may have restrictions when the currency in your balance is different. But, again, this is really just speculation and Paypal directly should be able to tell you more.
-TalionLosing my insanity would mean I'm losing everything: the dreams where I can fly.