Credit: Chris Weeks/

Sucks to be Spencer Pratt!

The former Hills star is so unpopular in Hollywood, even his agent won't answer his calls!

A source tells the new Us Weekly -- on stands now! -- that Heidi Montag's hubby, 28, still owes his agency "hundreds of thousands of dollars in commissions" from the millions he and Montag, 25, earned during their run on the MTV reality series.

The source adds that Pratt calls his agent up to 30 times a day. "They just laugh at him or pick up and hang up."

For more on Spencer's financial woes -- and much more! -- check out the new Us Weekly, on stands now.