Battery percentage isn't increasing

Hello. I have a samsung j2 phone and my first ever charger were working pretty well before but then i saw that it kinda broke and while it has that i still used it to charge my phone but then i saw that my battery percentage isn't increasing anymore even though it has that light bolt in it, it just doesn't increase. So i bought an another charger just for this problem, i tried it out but it just does the exact same thing, It doesn't work. What i mean, it just doesn't increase. So i tried my sister's charger, her phone is Samsung A6 (i believe, but it's smth w/ A) And it actually worked, im actually using it right now. so can someone help me. like why it doesn't work on my chargers but my sister's phone charger?