An embarrassing thing

Yesterday we went to buy some batteries in the electronic market. Since our purchase order demand is not big enough. The forward suppliers won't cooperate with us. In the theory, the supplier we went to yesterday can be called our qualified supper.Because its samples were confirmed by Headquarter. But it is noly a distrubution client.
The purchase gave me cash and purchase order. Since he had other job to do and asked me to help him to buy 60pieces batteries.
I had thought that he had solved all problems and I could obtain goods with the cash directly.
But when I arrived there and the boss saw the purchase order, the boss said the price was acceptable. I was puzzled and asked why. He said because the material price had raised and stocks price had raised. I knew she was blithering. But I have no other way. We need the batteries urgently.
Why the purchaser didn't confirm the price ? You are right. It is a good question. I am angry at the purchaser.
Later we had to buy the batteries in a higher price.
After being back, we detected the batteries weight was less than old one. I phoned to the batteries manfactory. A manager told me because the matterial had changed. The present weight is less 0.1Kg than the old.The old one is about 0.6Kg.
How can we do? One side we need the batteries urgently. Another side we have paid the cash to the client.