An FTX customer who says he shed $750,000 after the crypto behemoth collapsed has filed a lawsuit against the NBA's Golden State Warriors, accusing the team of fraudulently promoting the firm.

Elliott Lam, a Canadian who lives in Hong Kong, filed the proposed class-action lawsuit in San Francisco against Sam Bankman-Fried, Caroline Ellison, and the reigning NBA champions.

The lawsuit seeks $5 million in damages for non-US customers, adding that "thousands, if not millions, of consumers internationally" have been impacted by the downfall of FTX, which the suit claims perpetrated "fraud and deceit at a scale rarely seen.

Reuters first reported the lawsuit Monday. The Warriors are also defending a lawsuit in Miami filed by American FTX customers.

FTX filed for bankruptcy on November 11. The crypto exchange change was worth $32 billion before it plummeted to zero. Its court filings show that the firm has up to one million creditors, and a lack of oversight to the extent that it didn't have an accounting department.

Lam's lawsuit says the defendants falsely represented FTX as a "viable and safe way to invest in crypto."

It also alleges that the company sold unregistered securities through yield-bearing accounts, which gave interest on cryptocurrencies. 

The lawsuit alleges that FTX used "A-list celebrities and mass branding campaigns" to "drive unwitting investors and consumers into a Ponzi-like scheme."

Furthermore, as a successful NBA team, it has "unprecedented reach internationally" and exposed FTX's marketing to "millions of consumers."

The Warriors named FTX its "official cryptocurrency platform and NFT marketplace" last December in a first-of-its-kind partnership. It also saw FTX's logo printed on the Warriors' home court. CNBC reported that this deal was worth $10 million before the Warriors put it on pause last week. 

In the announcement, FTX's US president, Brett Harrison, said that its NFT platform "will provide a leading, safe and secure venue for the Warriors international fan base to access exclusive collectibles from the franchise."