I’ve made a couple of posts regarding “deleting” chat messages. What you actually want to do here is stop the message from being sent at all to any chat processor. Tritative answered this already; if you need extra resources, you can check out some other posts I’ve made on this topic:
https://devforum.roblox.com/search?q=delete%20chat%20%40colbert2677
(Also, please search before posting!)
There is an API method for deleting chat messages but it’s only for the most recent chat message sent, it doesn’t target specific messages and is therefore useless. Stopping the message from sending is your best bet, not trying to hack together a way to delete specific messages from the chat.