"could not get on their website...." is not the same thing as "Prudential cannot provide my 1099R.." What other steps have you taken to get the 1099R? Have you called them? Emailed them? Tried to contact them in any way ?
The penalty for filing a tax return late is 5% per month of the amount you owe, for the first 5 months, and 0.5% per month after that. In addition, there is interest charged on the unpaid balance, at a variable rate which is currently 8% APR (about 0.75% per month), with the exception that late payment interest is not charged in any month where you are already being charged a 5% late filing penalty.
If you don't owe tax, there is no penalty for filing late.
If you really can't get a 1099-R, you can file with a substitute 1099-R that reports the payments and tax withholding from your own financial records. However, it sounds like to just need to call Prudential and get them to mail you a copy.