Greetings sheinabg,
Thanks for using the Apple Support Communities!
I understand that you are having an issue with Messages for one specific contact. I also know how frustrating these type of situations can be, but we are here to help!
To begin troubleshooting this situation, I would suggest reading over and following the steps in the following article.
Sometimes your messages won't send to a particular contact, or you might have issues with group messages. For example, you might reply to a group conversation and receive your own message. Or you might get a new phone number and see your old one listed as a recipient in an existing group conversation.
Delete the conversation* that has the issue and start a new conversation:
- Open Messages and look at your list of conversations.
- Swipe from right to left on the conversation you want to delete. Then tap Delete.
- Open Messages, tap
, and enter the phone number or email address of your contact or contacts.
- Write a new message and tap send.
*When you delete a conversation, you won’t be able to recover it. If you want to save parts of conversations or their attachments, you can take screenshots. You can also touch and hold an attachment or message bubble, then tap More > Save.
If you can't send or receive messages on your iPhone, iPad, or iPod touch - Apple Support
Have a great day!
