MagSafe battery pack

Is my battery pack defective? It’s not even a week old and first time I go to use it, it charges for 30 seconds then stops charging but says it’s still connected to my phone. It was fully charged, when it connect it to my phone it blinks orange like 5-10 times then 20 seconds later stops charging. It’s not my case, it’s not the fact it’s not fully charged, it’s not charging my phone for more than 30 seconds then stops charging. Somehow the MagSafe battery pack loses battery yet my phone gains nothing.