Notice of account change /Sprint-we didn't receive the trade-in phone..

As the title shows, apparently I'm being scammed by Sprint/T-mobile. I have the proof of delivery and not sure why I received this ominous message via text only. No emails or any other information in the account that suggests that the phone that was traded in was not received. There was no confirmation that the trade-in was received by Sprint/T-Mobile either, but others tell me that's typical lack of communications on the part of Sprint/T-Mobile. What should I do? I tried calling Sprint customer service multiple times, but the wait times are 30+ minutes each time.