How can I sound this paragraph naturally?
This store negotiated with Goupon company. We agreed that We didn't continune to sell the coupon any more in Janunary 2019. Customer may come to the store consume directly. The price should be same with the online price of Goupon. If Goupon company didn't issue and inform customers and the customers still order the coupon. Please contact Goupon company for refunding. Sorry to cause any inconvenience. Thank you.

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Answer

Post it in the Notebook section. There are really too many corrections needed for here. It may pay to post the Chinese as well, to clear up any ambiguities in interpretation. 
Did you really mean Goupon? or Groupon?

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