My wife and I tried letting our teenager have her own cell phone, and that informed a lot of what I saw. We eventually found a locked down phone purpose-designed for kids, but I have no problem with getting a landline if it continues being an issue. (The issue with my kid and phones is not what we were discussing; she is on the autism spectrum, and so it is not quite the same; I have no idea yet what I will do with my neuraltypical son when he grows into a teenager)