He just tweeted an image of the BBB saying his university has an A by the BBB...

It should come as no surprise this is a lie...

http://www.factcheck.org/2016/03/trumps-defense-of-his-university/

Trump told Wallace that his program “had an ‘A’ rating from the Better Business Bureau,” a nonprofit organization that reviews millions of businesses by request and rates them on a scale from “A+ to F.”
The BBB website does not currently list a rating for The Trump Entrepreneur Initiative. It says that is “because BBB has information indicating it is out of business.”
But, in a statement to a reporter with PolitiFact.com, a Better Business Bureau spokeswoman said that “over the years, the company’s BBB rating has fluctuated between an ‘A+’ and a ‘D-.’ ” The spokeswoman declined to say when the program received the “A+” rating.
However, the most recent rating that we could find for the program was a “D-” in 2010. That is based on news reports from the Washington Post and the New York Times in 2011, and the New York Daily News and the BBB’s own website in 2010, as recorded by the Internet Archive’s Wayback Machine.