3B worng filled.

pay the difference amount in next month of return and file proper GSTR1 in that month of GST3B which you was wrong filed

Actually it was my 1st time and i have only 1 sale in the month of Oct 18 and by mistaly i clam itc of 3000 rs n dnt so any outward supply, but that 3000 Rs is came to my electronic lesur instead of paying that 3000 rs. and yes i submitted my gstr1 correctly so now what i have to do now. coz i dont have any itc in that month. so now how can i correct my mistake?