Text message Recovery

Restore your iPhone, iPad, or iPod touch from a backup
Thank you for using Apple Support Communities. Have a good one.

Hey, guy.

Try to recover your deleted messages through iCloud and iTunes if you had back up.

If you hadn't, maybe you should get some help of data recovery toolkit, such as iPhone data recovery to assist you to recover your deleted messages from your phone.

Begin to recover your deleted message as quickly as possible to prevent them to be over-written or you couldn't get them back anymore. So use this toolkit to scan your device and ensure whether your messages exists or not if you are not sure about it, it just needs a little time.

if you need to get more details, read the following article about how to do it with iCloud or iTunes and how to do it without any backup.

Hoping it will work for you and you could recover deleted messages from iPhone 6 plus successfully. Good luck to you!