Our system has frozen up?

I am angry with Worcester Bosch. We had a system for 30 years which never froze up. We had our present new boiler installed in April and for four days we have had no heat. Apparently if it says EA and the blue light blinks, it says on the answerphone, they will not come out. WHAT ARE WE SUPPOSED TO DO if everytime it is cold, the system freezes, surely that is a system which SHOULD NOT BE INSTALLED. If we reset it, it shudders badly, we are afraid of breaking the boiler