gas repair scam

we had issue with our gas for which we called https://www.vinaygasservice.com/contact/ they inturn shared contact [PHONE] this account is impersonating as representative of Mahanagar Gas Limited he visited the house checked gas and said there is leakage to fix it will have to pay 6805 I was at work told him to do the required work later when I checked the parts he replaced in open market they cost around 500 in total for which he charged us 6805 and the invoice he issued for it is also fake using GSTN number of Mahanagar Gas Limited which he is not authorised to do so he has scammed sever other people as well check his Truecaller record