Jermaine Jackson -- Deadbeat Dad AGAIN ... Allegedly

Just beat it ... deadbeat it ...

Jermaine Jackson is downright refusing to pay his child support bills -- so says his baby mama Alejandra Jackson, who's accusing him of falling behind on payments yet again ... this time to the tune of $30,000.

L.A.'s Child Support Services Department has filed legal docs asking a judge to hold Jermaine in contempt for failing to meet his child support obligation for April 2012 through April 2013.

According to the CSSD, Jermaine was ordered to pay $3,000 a month in support for his two teenage sons, Jermajesty and Jaafar (totaling $36,000 per year) but failed to make any monthly payment in full.

The CSSD claims Jermaine sporadically paid a total of $5,621 throughout the year ... and allegedly still owes $30,378.

The CSSD says Jermaine is guilty of 12 counts of contempt -- one for each month -- and it wants him sentenced to 60 days in jail if he doesn't pay up by August ... when there will be a hearing to address the issue. Calls to Jermaine's camp weren't returned.