How can I retrieve deleted messages from contact

You can do that if:

a) Messages in the Cloud is disabled (check under Settings > Your name > iCloud)

b) you have a recent backup that contains your messages

If you meet the requirements, you can restore your iPhone from that backup, but note that all of the data like photos (if not using iCloud Photos), messages, etc. will be overwritten, since there's no way to restore just the messages.