Need to have something in writing that say I pay my taxes for 2016 ?

Well, if you filed, you should have a file copy of your tax return.

Barring that, you can go on-line at www.irs.gov and get a copy of your tax transcript for 2016 about four weeks after you file.

This is why you should maintain copies of your tax forms for at least 5 years and preferably longer. If they (IRS) decide to audit you you will have records and copies of all deductions, without them its your word against theirs. If you paid a tax preparer to do them for you...many if not most will have copies.

How did you pay them? Do the return yourself?