GST Not Payment By Co-partner For My Firm

I jointly own a firm with a co-partner where we handle different lines of business separately as a contactor in PSU. I have been regularly paying GST against my business but my partner has not paid his share and doesn't intend to pay either due to which our GST account is locked. As the firm's common GST account is locked,the PSU is not paying my share of money as our firm has not paid GST. I have requested my partner to pay the amount but he is asking me to pay half the share, even though, I was not a part of his business. Please guide me to resolve this issue.