More trouble for ex-NBA player Sebastian Telfair -- this time, it's money problems ... 'cause the 2004 1st-round NBA Draft pick is now in the hole for more than $40k to American Express.
It's all in a new lawsuit obtained by TMZ Sports ... which shows the 33-year-old former high school phenom never paid his $43,051.69 bill to the credit card company -- and now they're trying to collect.
Shocking considering Telfair -- a once promising player -- reportedly made more than $19 million during his 10-year career in the NBA.