Still not receiving texts from someone I unblocked?

Since apparently the background story is important… I got into a fight with someone about 3 months ago and I blocked them from receiving texts and calls on my phone. A couple weeks ago I unblocked them and started mending the relationship. However I'm still not getting texts from them and I know I they've been texting me because I saw the persons phone and they have been sending me texts in a group chat. I have an iPhone 5s and in my settings it says I have no one blocked. How do I fix it so I get their texts again? Has anyone else had this problem?