Unable to block Messages from spam sender

Hi MayurRH,

Thanks for contacting Apple Support Communities!

We understand that blocked contacts via Messages aren't saved, correct?

If you check the list of blocked contacts in Settings > Messages > Blocked Contacts, do you see the blocked phone numbers listed here? You can learn more about blocking contacts, email, and phone numbers here: Block phone numbers, contacts, and emails on your iPhone, iPad, or iPod touch

"Manage your blocked phone numbers, contacts, and emails

To see the phone numbers, contacts, and email addresses that you've blocked from Phone, FaceTime, Messages, or Mail:

Phone

Go to Settings > Phone and tap Blocked Contacts to see the list.

FaceTime

Go to Settings > FaceTime. Under Calls, tap Blocked Contacts.

Messages

Go to Settings > Messages. Under SMS/MMS, tap Blocked Contacts.

Mail 

Go to Settings > Mail. Under Threading, tap Blocked."

What is your default account for your Contacts? You can go to Settings > Contacts > Default Account to check.

We look forward to your reply.

Cheers!

Hey MayurRH,

Since this sounds like unexpected behavior, we recommend reaching out to Apple Support directly for a closer look. You can reach them here: Contact - Official Apple Support

Take care.