Complete the following letter with a body paragraph of about 50

Complete the following letter with a body paragraph of about 50 words. Make sure that the tone and vocabulary you use are in unity with the beginning provided.
Dear Sirs,
I am glad to inform you that Barlow Knee Support has become increasingly popular here. It is indeed very effective in relieving knee pain and helps arthritis victims a great deal. Unluckily.
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By the way, we'd like to know if you still offer Free Bonus Gift. We would be grateful if you could give us a prompt reply. Thank you!
Yours truly,
Gan Ziyu
Purchasing Manager


【正确答案】：Unluckily, this medicine is completely out of stock. We are wondering whether you are still producing Barlow Knee Supportand whether you can sell us 1,000 pieces at the same price as you did three years ago.
【名师解析】:很遗憾地告诉您，目前我们的Barlow膝关节支撑器已经完全售罄。我们正在考虑您是否仍在生产该产品，并且能否以三年前的相同价格向我们提供1000件。