common problem with that year 300/charger, the hands free module has locked up, this is due to a software glitch that can show at anytime, there IS a software update to fix the glitch BUT first you need to determine IF you can unlock the hands free module.
to do this open the trunk and lift the spare tire cover with a 10mm wrench loosen the NEGATIVE battery cable and disconnect it from the battery for MINIMUM of 5 minutes, this will allow all the capacitors in every module to drain and "hard reboot" the modules.
then reconnect the battery and try the hands free "phone" button IF nothing still happens the module has failed and must be replaced.
if you wish to attempt it yourself it's not difficult BUT it's under the drivers side of the dash and TIGHT access for sure and you WILL be working blind in some cases you will need right angle screwdrivers with EITHER phillips or TORX (star) bits the bit depends on what was on hand at the assembly plant the week your dash was built.
if you want instructions i will need the vin
it's a plug n play module BUT you will need to pair any devices to the new module.
you're BEST bet is a new module since any used ones while will work won't be the latest hardware/software and some older modules had "issues" with newer phones/devices