PROBLEM IN RECTIFICATION OF AY 2018-19

I filled return of ay 2018-19 it was processed by CPC during processing rebate u/s 89 was not consider and demand generated I want to rectify but there is no option of AY 2018-19 on efilling portal so I gave Greviance to CPC . I received reply that call to helpline and given does not exist what should I do pl help me.