Not being paid what was agreed

Hi,



I would like your help in understanding my legal position here.



I was contracting at a company and then offered a promotion on a 12 month contract. I was offered a salary which was higher than that of my predecessor, to cover it being temporary and also no pension contributions.



I signed the contract at the lower wage, assuming the corrections would be done afterwards (very naive I realise in retrospect).



Now - I'm being paid the lower wage and am being told it was wrongly sold to me, and always should have been the lower number.



Please can you advise if I have a leg to stand on to push for the higher salary?



Thanks.

Not being paid what was agreed