lizgo

I have an E Class W212 2011 Estate. The command system has stopped working. It has been into Mercedes agents who advise it needs a new headset. After not working for a full year it suddendly started working! It worked for a couple of days, stopped and started again. It has now stopped working. Error message when it started working the other day read "Error on update:2020 Timeout"
Any advice or pointers greatly appreciated.