Landlord trying to pull a fast one?

My wife and I recently signed a 12 month lease with a property management company for a duplex in Moscow, Idaho that begins this June. We paid 1st month's rent along with a security deposit. Additionally, the property management company signed the lease and we have a copy.

We just got a call from the company saying they made a mistake on the lease where it explicitly says that "tenants will not be responsible for w/s/g", when in fact we are. However, both the running advertisement (we have a copy) and the lease says otherwise. Now, they want us to come in and amend the lease, saying we will pay w/s/g (which will be about 80+ extra dollars a month). Since it was their mistake they are also giving us the option to break the lease.

This extra $1000/yr. is a huge deal to us and it seems like they have no legal right to demand we change the lease. As the rep from the company said many, many, many times during signing, the lease is a "legal, binding document" and cannot be changed without each party agreeing. Can't we just say tough luck?

Help please!

Yep, their bad. They advertised it to say those utilities were paid and signed a lease to that effect. Refuse to amend the lease or terminate. Hold them to the agreement they signed. If they refuse, threaten to sue and state that they are pulling a "bait and switch" routine. They offered the place in the ad and signed that lease,. Now they have to live up to it. Or offer to terminate if they pay you to do so. You are in the right.