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No, you cannot use your UNI card to pay your other credit card bills. It can be used for online and offline purchase at merchant locations accepting VISA.
This is not a traditional credit card, and even with credit cards, you are not allowed to use it to pay for your other credit cards.
UNI cards can be considered as a personal loan or an overdraft facility. Your spends are split into 3 equated instalments of 0 interest.
Failing to pay the installments on the due date will result in a default charge. This late payment charge is added to your existing balance. They have a set late payment fee slab that is informed to you at the time of card issuance.
And repaying your balance amount in full by the due date will earn you a cashback of 1%.
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You can use your UNI card for purchase of goods from merchants who accept VISA. You can use it both online and offline. However, you cannot use the card to pay for your other credit card bills.
As of now, UNI cards are not available for international use. However, they are processing requests for them.
Overall, UNI cards are a good choice for someone with no credit history or a poor credit score. They allow you to avail some credit while you build your credit score.