2004 c270 radio "freezes"

[zappamob]

I recently purchased a 2004 c270 cdi avantgarde model. I live in belfast in Northern Ireland and travel to dublin in the republic of ireland. Everytime i come back up the radio freezes. This means i am not able to use my phone and it also burns an image into the screen of the radio. I have brought it to my local dealer 6 times in the last 2 months and they have not been able to sort out the problem. Does anyone know what is wrong?Grateful if you could help.

 

[joe bloggs]

There is a modified unit to cure this, meanwhile press together 'up arrow, left arrow and button 1 to reset it.

 

[Mark-Holt]

Sorry to post a question,I cant seem to find anywhere to post. Can any one help!! My husband has E class 2009 Mercedes, his radio just went off there's no power to it at all,any ideas as to fix it. Thank you