Phone suddenly turning off after battery replacement

Yesterday i had my battery replaced because the old one was bad.

I came home and put it on charger to charge it fully since it was dead.

After several hours it was 100% so i unplugged it. I was just reading something online when it suddenly shut down. I tried starting it and nothing showed. After plugging it back it showed that the battery was drained and it started and showed about 11% battery. I charged it to about 75% unplugged it and started messing around in settings when it went off again. After few of theese i noticed that the battery dies when it should lose 1%. For example it was 75% and rather than going down to 74% it lost all of its battery.

I had the battery changed at service and not at apple store because there isnt any near to me.