Battery connector doesn't match phone's connector
I bought my daughter a used iPhone 4S. Battery won't hold charge. Bought replacement battery, but phone's connector for battery lacks holes for 2 Phillips screws, is a different shape, but connector "fits". Interestingly, the battery conn. was held down by clear 2 sided tape, since it lacked screws to hold it down. Is this a modified phone?. Phone won't restart. Get Apple on screen, turns off, then apple reappears. See photos. Notice there are no holes for the two Phillips screws on the phone.