Barbers Cocktail Bar - Fake mojito

I bought a mojito here that disn't taste of anything except lime cordial and soda. When I mentioned it, the barwoman shrugged and poured more of a white spirit in on top. Afterwards, it didn't taste of rum anymore than the first time. It just tasted sharper. I decided not to drink it, when they saw that they came and asked me if everything was ok. I said it still didn't taste of rum. She snatched it away and came back later with another drink. To be honest I didn't touch it as I din't trust what was in it and just wanted to get out of there. I paid and left. We should have known it was dodgy as one of us ordered a pint and the guy was trying to talk her into getting a cocktail. She had to ask four times and he kept ignoring her and trying to push the cocktails. He was quite grumpy when he eventually relented and took her order. I am really disillusioned and will drink only beer from now on. A shame as the cocktails elsewhere were really delicious. Today I feel awful despite having only two small beers and a few sips of that nasty mojito. I can taste that sharp taste in my mouth. My throat feels like its been stripped and I have a headache. I rarely get headaches. I have a wierd hungover feeling that I just shouldnt have given the amount of alcohol. I get that people want to make money and wouldn't begrudge them skimping on the measure or watering it down but whatever i was given last night, it was not white rum. Messing with that kind of thing is dangerous. If I was drunk last night I may not have noticed and drank the whole thing. I feel bad enough today as it is, i would have been poisoned if I'd drink the whole thing. Not cool.