The saviour of West Australian debt collector Pioneer Credit has threatened to withdraw its support and end its deal to acquire the firm for $120 million after alleging the company has missed milestones, reneged on agreements and failed to disclose information pertinent to the sale.

Private equity players Carlyle Group extended a $260 million lifeline to the company late in 2019, which included a $120 million offer for its equity, after a horror year for Pioneer Credit that included a qualified audit, adoption of stringent new reporting standards and suspension of its shares from trade.