gati relocation packers and movers bengaluru - increase in charges after taking the custody of cargo

i was doing a relocation of personal effects from our rental flat from Bengaluru to goa , I got the quotation from GATI relocation packers and movers Bengaluru of inr **,*** on **th feb **** , accordingly we agreed for the same and the job was given to them , on *th march i paid an advance through google pay of inr **** ( google pay number ********** ( mr sunil swami ) , aand on **th march they came and did the movement of my personal effects , & i also aid the balance payment of ***** , and i was given the truck number KA**AG**** that the material has been dispatched from Bengaluru to Goa . On **th march i get a revised invoice of INR ***** from GATI relocation packers and movers Bengaluru , when i enquired why is the sudden increase they said it was wrongly calculated and this is the amount to be paid else they will not hand over the cargo at destination, so i had no option but to pay in protest the balance amount of INR **,*** on **th march.