Can I cancel apartment rental (leasing, live in, law)

[moscas]

So we don't live in the US yet and we tried to rent an apartment for 3 months for my mother in law, my husband and myself. The lady from leasing office sent us the lease by email and we all had to sign it. I was the only one that signed it so far. The lady accepted us for the 3 months but we couldn't be there to turn in the money order she required to pay the deposit and first month's rent. So we sent the lady the money via Western Union. This happened on Friday, and it was too late for her to cash the money at the bank and will do it on Monday. On Saturday only my husband and I arrived and signed and initialed some documents she gave us. She gave us the key and showed us the apartment. We don't like the apartment and we would want to cancel this whole thing. I don't even know if we have a valid lease because my mother in law hasnt signed it yet. The money is still in Western Union.