It started to happen yesterday night from data balance messages from Airtel. I had message preview and pop-up notification on in message settings.

When the messages came in, probably because I didn't click from the notification bar but clicked the message app, I could not see the new messages but the notification banner still read 2 on the message app.

Saving incoming messages on my sim is off and even when I deleted all messages the notification banner did not go. The only time I see the new messages is when I search for them and even at that I get "0 messages of" the message as a reply.

How does one solve the problem without resetting the entire phone?

I have not updated the phone since I bought it. However, if the solution is updating the phone, I feel like updating has the same effect as resetting or formatting the phone since it messes with the files in your phone memory. At least that was the experience I had with my Infinix Hot 2

if you still have messages on your phone trying opening all of it and scroll up and down from the beginning and end of every messages like you are reading them. that might help.

giftedben:
if you still have messages on your phone trying opening all of it and scroll up and down from the beginning and end of every messages like you are reading them. that might help.

I deleted all my messages. There are no messages on the phone.