A : Good morning. Accounts Payable

A : Good morning. Accounts Payable Section. _____A_____ speaking.
B : hello,___A____. This is _____B____ .
A : Hi, ____B____. May I help you?
B : one of our suppliers, IT network corporation, hasn't received payment for their last shipment.
A : one moment, please, let me check.
B : that's good.
A : There is a problem.
B : what seems to be the problem
A : I received the Purchase order and goods receipt from your department last. but when i compared them to the tax invoice, I found some discrepancies.
B : Oh, what were they?
A : the unit price in the purchase order was 27,000 baht but it was 29,000 baht on the tax invoice. i also found the wrong price in the collection bill sent by the supplier
B : Oh, really? I didn't know that. 27,000 baht was the price we agreed in the contract. I don't know why the price was changed in their documents. I'll call them up immediately and look into the matter. then, I'll let you know the details.
A : Thank you, I’ll look forward to your call.
B : OK. Bye.
A : Bye.