Why does my iPhone 5s keeps restarting after minutes of using it?

Hey guys! So i had my first iphone issue before, my iphone 5s keeps on shutting down and drains its battery after minutes of using it, so when i had that i problem, i keep using my phone while connected to my laptop until it never turns on again. So i decided that maybe my phone needs a battery replacement. I recently had my battery replacement but another issue occurred, my phone keeps on restarting after minutes of using it and the battery logo keeps on changing numbers, after restarting it shows 1% then suddenly changes to 100%. I am planning to visit the technician this afternoon again. What should I do if it still doesn’t work? I hope someone could help me. Thank you!