How do I declare income earned when I haven't received a 1099 and cant get any EIN information from the company?

It depends on what the payment was for. If it was work-related, the employer should have 1) withheld taxes and issued you a W2 or 2) issue you a 1099-MISC as an independent contractor, in which case you file as self-employed and pay self-employment tax.

I know I need a 1099. But what do you do if you can’t get the company to issue one?

So are you wanting to file as self-employed and do you have any proof that this payment was made, such as a canceled check?

Yes I suppose I need to file as self employed - even though I received only check. And I did keep the canceled check

You do NOT need a 1099-misc or the company's EIN. 

Although it may be news to you that you “have a business”, the IRS considers undocumented cash income (no W-2 or 1099-MISC), for work performed, to be self employment income.  You report the income from your own records. Enter at "Business Income & Expenses" and TurboTax (TT) will complete Schedule C or C-EZ for you and allow you to deduct any expenses associated with this income. You'll also have to pay self employment tax (social security & medicare tax) on any profits greater than $400.

Do I need to set up as a company for my business?  

No. As a self employed person, you fie a schedule C, as an additional form (added to your 1040). You use your name and SS#. There is nothing to set up.