For anyone who used Tax1099.com to file 1099-INT

My mom passed away last year, and we owned a CD jointly with her as the primary (so her SSN). The interest earned since her death went to me. I used Tax1099 to issue a 1099-INT from her to me on February 15. It is still showing "submitted." Today, I received a hardcopy 1099-INT that I ordered from the IRS, but the deadline for paper forms is Feb. 28. Do I keep waiting for the IRS to accept the 1099-INT electronically, or should I mail the paper form? I'm afraid mailing the form could cause problems if/when the electronic form is accepted.