If you are unable to delete then you must live with your decision to have included them in the first place. Just one of the many reasons I object to the Friends List - it causes more problems than it is worth.
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4.
Make them wanted - give them chance - win over them. It is a challenge - accept it. I fear this reply may again make me unwanted to you. if not- I will feel lucky.
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9.
It is better to tell the friend the things or the Quality you don't like of a friend and if there is no improvement , you may delete your friend from the list but remember , you cannot join the friend again in future.