Credit Score Credit Card Cancellation

Question: AMX canceled my credit with them because of non-use. Will Credit Score suffer?
I've been a member of American Express for 15 years but haven't used the card in many years. I had no balance. My Credit Score is 770s to 790s depending on the reporting service. I never carry a balance on any of my other cards (3 others) and have not missed a payment in more than 10 years.
We're looking to buy a house right now, so credit scores are very important to us right now. Will this cancellation effect my score? The only reason stated is that the card hadn't been used in the last 24 months.
Answer: Do not close the card cause it lower you available credit line. You also can use this service to pre-estimate future scores for different scenarios of credit card payments. - freecreditreport.hotusa.org
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