underpaid after i left my job

yesterday i got paid from tesco but was underpaid by at least £100 and as i have gone back to university i can't go there to ask about it. I don't have any contact information for the place and the phone number on google is not in use. As it is a fulfilment centre and there aren't customers directly going into the store i think it's much harder to contact and on the tesco store list it doesn't even come up. also there is no contact information on the payslip.

does anyone have any ideas on how i can contact them and try and get my query looked in to?

and i still had holiday left so that's definitely not the case as i didn't even take any holiday the last month i was there

Neither of those mean you hadn't taken more holiday though. Say you have 24 days holiday per year, if you take 20 days in the first 4 months, then none for the next 4 months, then leave - you have only worked there for 8 months, so are only entitled to 8/12ths of 24 or 16 days' leave, so you owe the company 4 days. They will take the equivalent of 4 days pay out of your final pay packet.

Chances are you have took more holidays than entitled therefore you get money deducted.