Returns of prior period

Dear Experts,
a client had taken GST reg. in 2018 and has not filed any quarterly returns till date. now he wants to cancel reg. and applied for the same. however department is asking for submission of pending return. while filing GSTR4/Comp8 portal shows late fees of Rs 19000 for the Q1 of FY2018-19. Please advice in this regard to cancel his reg.

thanks in advance