I agree that misunderstandings can cause problems. That is the trouble with doing things on the phone. I much prefer to do things in writing, whether by email or letter to confirm what has been agreed so there is no room for subsequent dispute.
For example, Norwich Union insist on describing my car as having"Replacement seats". In fact it has standard Chili pack seats and I have it in writing that that is what they mean. Not a problem in this case but it emphasises the scope for misunderstandings.