The listing has been stopped.
https://www.asx.com.au/asx/share-price-research/company/COW
https://www.asx.com.au/asx/statistics/announcements.do?by=asxCode&asxCode=COW&timeframe=D&period=M6
If you have shares in the company from being supplied them by Tawana then you are currently a shareholder in a private unlisted company, with your holding managed by ComputerShare Australia.
Logging into ComputerShare will show "Cowan Lithium Limited" and the designation "Unlisted".
In this case, you are a shareholder, but trading your shares via the ASX sharemarket is not possible.
You may be able to trade your shares directly by contacting your broker, however you may be required to identify the buyer+seller yourself and other fees may be involved.
Any further questions, please phone the company directly with your concern/queries.