Bourdais admits he failed
Frenchman Bourdais, 30, last week accused his former employers Toro Rosso and Red Bull of lacking "style" by not facing him as they broke the news about his ousting in favor of Spanish teen Jaime Alguersuari.
"I told Monsieur Bourdais personally that he is not going to drive any more and did not write any SMS," Toro Rosso team boss Tost told Germany's Sport Bild.
He added of Bourdais: "I can understand that he is disappointed, but his performances were simply not what we expected.
"We wanted an increase in speed from him in his second year and it did not happen," said Tost. "On the contrary: our youngster Sebastien Buemi, in his first season, was better than him."
08/13/09 (GMM) Sebastien Bourdais has accused his former employers of lacking "style" by sacking him by text message.
The 30-year-old Frenchman was told his services were no longer required at the Nurburgring, and he was replaced thereafter by Spanish teenager Jaime Alguersuari.
"The way they got rid of me was very disappointing," Bourdais, who recently reached an out-of-court settlement with the Red Bull-owned Toro Rosso team, told the French magazine Autohebdo.
"Dietrich Mateschitz was at the Nurburgring but he did not speak with me. He did not call me. Everything was done by SMS, which to me has no style," he charged.
Bourdais, however, admits some blame for his failure to shine in two and a half seasons at Toro Rosso, whose team until 2009 received the basic chassis designed by its parent Red Bull.
He said the car was not built "around a driver", but rather it was the drivers' responsibility to adapt "to the car. That was never my best strength," Bourdais admitted.