For have the access to the phone you need to do the next steps, first meet amy in the pool and get eaten by her, when you stay in her stomach you need to rest and wait for the next stage when she is going of the pool in that moment you start to talk to he and she give you the localitation to the lab of amanda, when you out of her belly you go to amanda and talk to she you go to the option for buying and in the final option you see the phone and with that you have it, btw the phone its free