Sarvana Furniture — Difference in Purchase date and invoice date

I have purchased one Sofa from Saravana furniture store Padi on dt[protected] and delivered on dt[protected] but in invoice the date mentioned is[protected] instead of[protected] I went to Saravana Store and denied they can't change invoice date so do the needful as I have made the full payment on dt[protected] so invoice date should be[protected] not[protected] as per purchase rule