I bought iphone 6 4 minths back! Now it has crescent gate issue! Service centre says for repair! Shouldn't i be getting replacement?

YYou can return/refund your purchase during the first 14 days after the purchase. After that you get a refurbished replacement that is guaranteed to be "same as new.' In practice this means the unit will have a new case, new battery and whatever else needed to be replaced.

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