Sorry to disagree, but it works perfectly for me. Never failed in any way and I'm using pretty much everything it has to offer (repeating vibrations, repeating sound notifications, the led itself and much more)...
Are you sure you activated the service in accessibility settings + access to notifications in security settings?
#1: Samsung Omnia 7 _ sold on eBay.
#2: HTC HD2 _ sold to my brother.
#3: Samsung Galaxy S2 (GT-I9100) _ sold to a friend.
#4: LG Google Nexus 5 (Hammerhead) _ my current beast! <3
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".: ~' Das war erst der Anfang deines Endes! :.