Go to Home > Settings > Audio Profiles and check the settings for ringtones, notifications, vibrate etc.
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=== Update (11/04/2016) ===
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Hi,
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Try making or receiving a call and then switching to 'loudspeaker' mode to check if the loudspeaker is working. This is the same speaker that is used for the ringtone. Nothing to do with the vibrate however.
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If it doesn't work then as the phone is only 2 months old I suggest that you consult the warranty documentation that came with the phone as to what you have to do to make a claim for a warranty repair or replacement.