Mustard 's personal life is getting ugly again ...

he says his ex-wife is bashing him on social media, even though they agreed not to talk trash about each other ...

and he wants a retraction. According to new legal docs, obtained by TMZ, divorce attorney Samantha Spector claims the music producer's ex-wife, Chanel Thierry , has been violating the judge's order that they both refrain from trashing each other in public and online. In one example, Mustard claims his ex tried to paint him as a deadbeat dad by falsely claiming the $275,000 equalization payment he made in their divorce settlement was only going toward back child support.

On the contrary, Mustard claims the money wasn't limited to back child support ...

he says it was to balance out all the luxury cars he kept in the divorce ...

and he says he most certainly is not the deadbeat she's portraying him to be. What's more, Mustard claims his ex released his private medical information to the masses when she posted online that he falsely claimed he had cancer. Mustard says Chanel's posts about his medical history are "beyond the pale.

" And, get this ...

Mustard believes Chanel was also talking about him when she referenced a "Gemini narc" in other posts online. He thinks she was talking about him because he's a Gemini. Mustard says Chanel eventually agreed to delete the posts, but he says the damage was already done in the media .

.. and he says she needs to retract what he feels are harassing, false and defamatory statem.