Given the bad press AZ got, reverting to a "no comment" strategy is not such a bad idea. Anything they say will be used against them anyway.
A company that just avoid commenting on issues your product could have or misinformation regarding it does not seem a company that cares about that. Hard for me that they had a good PR strategy.
The AZ contract has none of that. Ultimately, it would need a court to decide that. Once the point of discusing contract terms, the relation ship between supplier and customer is already ruined.
I just see a bad behaviour and PR from AZ. That and having a CEO that says that UK got it first because of the "best effort" clause when both UK and EU contracts have does not seem very professional to me IMHO. I am not sure why that happened.
Unless I am going to refuse any and all drugs and medical treatment, I will have to trust e.g. EMA that the stuff I take when being sick is safe and working as intended.