It's very poor that letters continued to be addressed directly to the husband, at the very least should have been addressed to whoever was managing the estate. And sending the Christmas card is not acceptable. Companies have to make sure that these issues are taken out of the automated system and handled by a human. It's a pity we don't know the timescale of all this though as I'm little puzzled why there is no actual mention of the estate attempting to settle the debt? If it had got to the stage of debt collectors that suggests a certain lapse in time.