Issues deleting text messages galaxy s3

[shoob0x]

I have a galaxy s3 and i have a text message conversation thats huge, well over 20,000 texts. I cant delete it. Whenever i try it just locks up and when i go back into the messaging app its still there, as if nothing ever happened. Is there any way to delete it other than a factory reset?

 

[shoob0x]

I used go sms pro to delete it.