It is addressed to me and says...
Please provide the following documents in connection to my UK Settlement App.
an employment letter from your employer
a bank statement starting from June 2016 showing your salary
And that I should send them to the Visa sheffield home office email.
I didn't copy paste, because it says not to, but that is almost identical to what it says!
Ah, okay, despite the wording, it HAS to mean your sponsor's employer letter and his bank statement from June 2016... because there is no reason for them to need a bank statement from June 2016 from you, or an employer letter.
Which months of his payslips and bank statements did you send with your original package?
If you applied on 17th January (as your previous post mentioned), it was mandatory to send ALL of your sponsor's payslips and bank statements covering the entire period from 17th June 2016 to 17th January 2017.
So, if you didn't include his June 2016 payslip, they can't issue the visa... which will be why they requested it. Same goes with the employer letter - if you didn't send a letter from his employer in the original package, they also cannot issue the visa.
And if you didn't send both of these, they will have no choice but to refuse the visa.
I guess all you can do for now is maybe try to re-send the correct documents, explaining what happened, and hope they accept them. However, since it's been over a month, I'm not sure they will consider them now, since it will be past the deadline they gave you.
Otherwise, you're just going to have to wait until they make a decision and mail everything back to you.