Looking on the internet deeply has found these results:

i will get back to you is the most popular phrase on the web.

i will get back at you 11,170,000 results on the web	i will get back to you 128,500,000 results on the web More popular!
Some examples and use cases from the internet:	Some examples and use cases from the internet:
I will get back at you with some shiny new developments, okay? Look, let me just go and I will get back as fast as I can. And I will get back to you with what I find as soon as I can. And I will get back to work. Ladies and gentlemen, I'm here tonight to tell you I will get back up. Well, I will get back to the outer layer... If knocked down, I will get back up every time. Look, let me just go and I will get back as fast as I can.	You know what, let me check on the head count and I will get back to you with a number. Well, I got to be somewhere, but I will get back to you. Let me check the details and I will get back to you with the results of my enquiries. I will get back to you on the detail when I have had a chance to study the matter. I will get back to you with the name you wanted shortly. I will get back to you on all of this later. I will get back to you on all of this later. I will get back to you very soon.

i will get back at you

11,170,000 results on the web

i will get back to you

128,500,000 results on the web

More popular!

You know what, let me check on the head count and I will get back to you with a number.
Well, I got to be somewhere, but I will get back to you.
Let me check the details and I will get back to you with the results of my enquiries.
I will get back to you on the detail when I have had a chance to study the matter.
I will get back to you with the name you wanted shortly.
I will get back to you on all of this later.
I will get back to you on all of this later.
I will get back to you very soon.