Democratic presidential candidate Andrew Yang laced into MSNBC Saturday, accusing the network of systemic unfair treatment and publicly refusing an offer to appear on air until he received an apology.

“Was asked to appear on @msnbc this weekend – and told them that I’d be happy to after they apologize on-air, discuss and include our campaign consistent with our polling, and allow surrogates from our campaign as they do other candidates’. They think we need them. We don’t,” he said in a post which was retweeted more than 9,000 times in a matter of hours.

“They’ve omitted me from their graphics 12+ times, called me John Yang on air, and given me a fraction of the speaking time over 2 debates despite my polling higher than other candidates on stage. At some point you have to call it,” he added in a follow up.

MSNBC declined to comment.

Yang, an entrepreneur who has never held elective office, is one of several outsider candidates looking to break through the crowded Democratic field.

Though he has raised millions of dollars, Yang has frequently griped about not being included among top-tier candidates by the liberal network.