Regarding problem of two gstin generated

I have applied for one GSTIN and i got GSTIN on 16th aug 2017

but on 13th sep 2017 they cancelled my old GSTIN and now i can't login into my old GSTIN and granted 2nd GSTIN without any application. i.e. i have not applied for 2nd GSTIN.

I want to continue with my old GSTIN because of sale and purchase bills are already made...what should i do?