Collect calls from jail rarely work on cell phones, and most carriers have moved away from supporting them entirely. The fix is straightforward: set up a prepaid account with whatever phone carrier the jail uses.
Every county jail contracts with a phone service provider, typically a company like Securus, GTL, ICSolutions, or Telmate. That carrier manages all calls made from the facility. To receive calls without the collect call barrier, you need to create an account directly with that carrier and deposit funds into it. Once the account is funded, your inmate's calls come through as prepaid rather than collect, which works on cell phones without any issues.
To find out which carrier your jail uses, call the facility directly and ask. The front desk or a counselor can tell you the provider name and often point you to the website where you set up the account. Alternatively, the next time your inmate tries to call, the automated system that plays before the call connects will typically identify the carrier by name.
Once you know the carrier, go to their website, create an account using your phone number, and add funds. The process takes about ten minutes and the account is usually active immediately.
If the per-minute rates through the carrier feel high, InmateAid's discount phone service is worth looking into alongside the prepaid account setup. Depending on the facility and your location, it can reduce the cost significantly by routing calls through a local number at a lower rate than what the carrier charges for your current number.