I got the same letter for a repair on an iphone 7 with a non working power button. It is under warranty but they returned it un-repaired with a letter saying that the mail in service is intended for individual customers and not for commercial enterprises. I do buy and sell a few iphones but not that many. And it is under warranty. I guess they want me to drive downtown to the Apple store, show them the problem, tell me they can't fix it and then have them send it the repair facilities. Seems like a waste of resources. I could take it to an authorized repair shop also, which is closer. But, the result will be the same.
