Craigkawasaki12

Hi all i have recently purchased a vivaro sportive with a infotainment system with bluetooth installed. my s4 phone connects to the system automatically everytime ignition is turned on without fail. The problem i have is that trying to make a call via handsfree works intermittently with full or very low reception but does state connected to both phone and dash display. I have reset and removed existing paired devices and still the same. Any help appreciated