In the beginning top - after 4 months badly - very good customer service

I have decided after a long search on the internet for these batteries because I read a lot of good things about it.
Now I go through the reviews and unfortunately can confirm the negative.
I own the batteries for 4 months and now holds the smartphone not even 12 hours at low (!) Use (60-70% of the day in standby).
I am going to try the second battery if it is as short-lived, I can not recommend these batteries.

Update: After I was contacted by customer service, I got extremely fast and free of charge a new battery.
Unfortunately, this holds even 10 hours a day with very little use of smartphones.

Conclusion: Customer service highly commendable, satisfaction with the battery is not given to me.