Stripe Payment Form / Token Error - Immediate Fix Required

We have a website which uses stripe as a payment provider. I tried to do a live transaction and got this error No such token: tok_; a similar object exists in live mode, but a test mode key was used to make this request. I'm sure its a 2 minute fix but I know nothing about stripe! If you do want to bid please do so at your normal rate, make sure you know stripe and its API well and can start now :)