my mother has an iphone 6 plus, and for some reason she can't click anything on the screen and it's been frozen on the same screen, is there anything that can be done here, and how much is it?

Deontae, The 6 plus model was plagued with a digitizer IC chip problem. It causes the phone to not respond to touch, even if the display hasn't been cracked. That issue is usually more expensive to fix than the 6 plus is worth. We have a nice stock of pre-owned devices arriving this week if you don't want to spend a fortune on a replacement phone. Feel free to give us a call Monday or stop in. There is a good chance we can recover the data from that 6 plus and transfer it to another phone.

Something you will have to ask them directly. I have had two phones fixed threw them and it has been fast and good quality repairs. My experience with android and taking to various phone maintenance people issues like that could be as simple as her having to much memory used on the phone. Phones do not have dedicated memory for operating and will let you max out the memory. I have been instructed to leave 15 GB of memory free at all times or my phone will start acting weird. My phone stopped calling and texting and various other things because I only had 5gb free of space. Repair wont be cheap but definitely better than buying a new phone