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Being unable to receive texts, especially if they're from people you communicate with often, would definitely be frustrating! The only possible solution left here would be to try delete the contact list entry for these 3 people from your phone. It's possible their contact is corrupted and it's causing these issue.
Should that not work, then we have to take a look into the status of these escalated tickets and possibility send off another if neither were able to find a solution.