Thank you for patiently waiting. As per checking here, we can retrieve the usage of the lines of the account but for the specific messages I'm afraid to say this but we have a limitations on our end due to security purposes.
https://www.t-mobile.com/support/account/check-your-usage
We don't have any access to get and transfer the messages its just for the security of the customer, but if the messages was back up, you can easily sync it to the number you want to transfer,
Sure! You can definitely call 611 or 1-800-937-8997 to reach our technical team. Rest assured that all the information are all notated here on our end so you don't need to repeat everything to our Technical care. . There are two options to check detailed usage. One is to check usage by downloading your billing statement it should be located on the last page. Second, Please follow these steps to view the usage.
You can follow these steps to view your usage:
Log in to T-Mobile.com.
In the top menu, select Usage.
When the usage details display, choose the type of usage: Data Messages Calls Mobile Hotspots Data Pass
Select the line you want to view.
Choose Download all records.
Save the file to your desktop, then open and print it.