Coca cola wateted down and sold in big retail stores

I bought a 2litre coke at game today... it was the most disgusting ever. Got 3 other people to taste it just to check if my taste buds were on point and got the same reaction. It was watered down and just horrible with minimal gas.

I am complaining abt this product even though it was bought from a retail store. They hv advised me they cant do anything about it.

I would like to know what this nrand is planning on doing because this is unacceptable.

Who do i speak to and what is the process...