Hello Harribobs,
Make sure the number is still blocked using the steps here: Block, filter, and report messages on iPhone – Apple Support
"Block messages from a specific person or number
- In a Messages conversation, tap the name or number at the top of the conversation.
- Tap the info button, scroll down, then tap Block this Caller.
To view and manage your list of blocked contacts and phone numbers, go to Settings > Messages > Blocked Contacts. See the Apple Support article Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch.
If you don’t see the option to report spam or junk messages you receive with SMS or MMS, contact your carrier. See the Apple Support article Wireless carrier support and features for iPhone."
If the number is still blocked and you are getting messages, we recommend restarting your iPhone and keeping it updated as those steps assure you have cleared out any minor software issues and are running the most current version.
Restart your iPhone - Apple Support
Update your iPhone or iPad - Apple Support
If you still have questions, reach out to Apple Support directly, as this may require closer guidance: Get Support
Cheers!