The FBI should already have THAT information. Report #7 is 1000 pages long and Feinstein looked like she was about to cry when she left the room. They may have deleted their iPhones -- but this is 2018. EVERYTHING is permanent.
Kavanaugh and Judge should file a civil lawsuit for defamation as soon as Kavanaugh is, (or isn't) confirmed, asking the court to preserve all communication records.
Also, if anyone was wondering why it took two days of testimony for Judge to tell the FBI, “I don’t remember anything”...