Faulty power bank

I have the Nintendo switch version of the Anker powercore 20100 mah this is new and I have been trying to charge it with first a 2.4 amp charger for over 24 hours and then I got a power delivery charger that gives a full 3a charge on all the voltages from 3v to 20v and it is compatible for charging the Nintendo switch I charge the power again for 24 hours with the power delivery charger but still I only get 1 blue flashing light and every time the power bank is being charged I never get a flashing light to tell you it is plugged in and being charged all I get all of the time is just 1 blue flashing light when I press the button. I have also tested the cable on many devices and it charges perfectly on normal and fast charging chargers. Is this a faulty power bank and also I have looked online and it says if a power bank has not been used fir a long time it can be rendered useless and fail to accept a charge I have contacted Anker and they don’t seem to want to answer the question of are these power bank’s rendered useless when not being used for a long time because if a retailer has an Anker product in stock unsold for some time they could be selling faulty devices to the public Anker should be informing the retailer’s about the time span of there device before it is rendered useless then the retailer doesn’t sell out of date power bank’s. Any help regarding this matter would be good thanks

Typically, power banks are sold with about a 50-75% charge and can be stored for months (or years, depending on the unit) in that state. However, it’s possible that the retailer did not store the power bank properly (perhaps on a hot delivery truck, etc) rendering it faulty.

Please feel free to reach out to support@anker.com stating the issue you are having (charging over 24 hours but you can not get past 1 blinking dot) for warranty service. Thanks!

I have a similar issue but it shows fully charged with 4 light on after being plugged in then when I try to charge other devices I get one blinking led. Wanted to see if you got issue resolved or just junked it

Support@anker.com should be able to help. Anker customer service is really great. Depending on your warranty and the situation they might give you a new one or propose a solution to fix it