It appears from the limited information that you have provided that the lease is defective. However, if you are already in occupation this could be difficult.
Is the area you occupy the same area that you though you were taking a lease over? If so, this could be problematic as if the matter was before a court, the court would look at intention.
At this stage, I would suggest you try to ascertain whether you can terminate the lease under the provisions contained therein. There may be a clause in your lease which allows you to serve notice on your landlord and terminate the lease.
I hope this answers your question. If so, kindly rate the answer and provide feedback.
If you have any further questions, please do not hesitate to ask.
I would suggest that you contact the landlord and inform him that the Lease that you have is defective and as a result you wish to forfeit the lease. You will need to do this in writing.
If you had someone act for you on the acquisition of the lease, it may be worth you asking them to contact the landlord on your behalf.
The alternative is that you terminate the lease in accordance with the provisions contained within the lease itself.
I cannot do this. The site is designed to provide general information. I cannot act for you. However, I am happy to check a letter that you have drafted and let you have my comments.
If you have any further questions, please do not hesitate to contact me.