To block someone is a very difficult decision. but if you want to do this , follow my instructions.
open a profile of a user or page you want to block. and click on top option to get options men like this
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select option "Block" like this
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if you are clear enough to take a decision then select option "yes i am sure " like this
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now if you want to see whole list of blocked persons.
go to your Instagram profile and click on top right option to go to settings menu like this
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now select option "blocked users" like rhis
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you will get a list of blocked users like this
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if you want to unblock it. then click on blocked user. its profile will open. and click on top right option like this
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now click on option "Unblock" like this
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it will ask you whether you are sure or not...
click on " yes i am sure"
ans user will be unblocked...
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thankyou.....