Generally, if the guarantor was not a party to the lease there isn't much he can do in this situation. After all, that is the whole point in having a guarantor in the first place. However, I would suggest that you have an attorney take a look at the lease to see if in fact it is legally binding. Sometimes there are ways to challenge these. There might also be other recourse available including perhaps trying to somehow negotiate out of the lease. Assuming its more than a one year term it might be worthwhile to pay some money for a legal consult.