Unless you have already had the software in place, the only way I know of (if it's your phone) is to call the provider and request a copy of the transcripts.
If you didn't save more data onto the phone in the last 15 days, two Android data recovery software might help, Easeus mobisaver android and Dr.phone. You need to connect the phone the computer to recover the photos.
If they are not overwritten, it's possible. You can use a Samsung data recovery program to get them back, such as Coolmuster Lab.Fone for Android. It helps us access to all deleted text messges on Android and recover them to computer via usb cable.