How to permanently delete someone off your iphone?

So I'm trying to permanently delete my ex's number off my iphone 4. I went ahead and deleted him off my contacts but I notice when I create a new text message and type in the first two letters of his name in the bar where you input the contact you are texting, his name and number still pops up in the drop down menu along with any other contacts I have that have a similar name starting with those two letters. How do I remove him from this drop down menu? I thought I permanently deleted his number by simply removing him from my contacts but I guess not.

Added (1). @Vespera Tried that and restarted my phone. Nothing. :(

Try going to options and delete any cache and temporary files / cookies. Im not sure if that will work, but its worth a try.

Anna, did you ever figure this out?

I'm having the same problem as Anna is there any solution to that