I heard the following phrase in response to someone claiming that he had researched documents about some historical figure. The person who had opposing idea commented with:
かけずほど当てにならない
From the context I guess it must have meant something along "I won't argue with written things" (more literally "If it's not written down, it can't true"), but the use of かけずほど is a mystery for me.
Could it be 書けずほど? What would be a grammatical rule behind it? Or could I have misheard it?