Judge Saundra Brown Armstrong reversed the restraining order against SpamCop and brought forward a hearing on OptInRealBig's case against case to next Tuesday.
OptInRealBig, which is run by "spam king" Scott Richter, took legal action because it said SpamCop was interfering the firm's business.
The judge placed the order because paperwork from SpamCop was said to be late.
IronPort bought SpamCop last year. SpamCop contacts ISP complaints centers when it receives spam reports from users.