I withdraw funds from my 401K retirement early. My employer did not and would not provide a 1099-R when requested. How do I enter this information into my taxes?

Your Employer is not responsible for sending you the Form1099-R for the distribution from your 401(K).  You need to contact the financial institution that holds your 401(K) account to obtain your Form 1099-R.  Alternatively, you can most likely download the form by logging into your 401K account.