He politely explained he was there to do some campaigning himself.

When I politely explained the situation, these passengers almost always pulled back.

The dealer stopped her and politely explained that the betting was over.

I was in the wrong place, he explained politely in reasonably good English, then offered directions.

The detective politely explains, "The trial is in a month."

There is no phrase in Korean, officials here explain politely, for "reform."

It was a matter of cost, one official explained politely when I inquired.

So, politely and reasonably explain to the supplier that it is his/her responsibility, not the manufacturer's.

Most of the calls were for Jan, and he politely explained that she no longer worked there.