I apologize in advance that this post is not helpful to you. It’s because I do not know the answer to your question. But I wanted to thank you for being helpful to me: Thanks.
Like you I have, for my entire life, always filed my taxes with the IRS by mail. No exceptions!
This year, for the first time, it appears I will be filing online. It will be a significant learning curve for me to ascend. However, the number of horror stories out there today, from people like yourself who filed by mail, is overwhelming. The situation is sufficient to force me to alter a lifelong filing habit.
On your question, and bearing in mind I’m guessing:
I should think, if you wait an eternity and after you suffer their wildly annoying automated responses, that you would be able in the end to reach a human being at the IRS. But that is not the voice of experience speaking. I really do not know and, as I said, the horror stories are numerous. 
ETA
One additional point:
My reading is telling me that the principal and primary cause of delayed refunds is a problem with ones return. When there is an error, anything at all, it forces manual intervention by IRS personnel. And they simply do not have the manpower to deal timely with all of the faulty returns.
I assume you have copies of what you filed last year. Were it me I would be going over my return “one more time” with a fine toothed comb. This might not speed things up, but at least you have the chance to discover the cause of the holdup.