Tenant not complying with Rent to Own Lease

[Carl Hobel]

Need to know if I need a real estate attorney or not.  My tenants lease to own contract is expiring at the end of the month.  The lease has a Notice Required To Exercise Option which states as follows:

To exercise the option to purchase the tenant must deliver to the Landlord, a written notice of Tenants intent to purchase, not less than 30 days prior to the expiration of the lease term. In addition, the written notice must specify a valid closing date. The closing date must occur before the original expiration date of the lease agreement.

My tenant did not notify me with a written intent to purchase or inform me of a closing date.  I told them that they did not comply with the terms of the lease and I would now be raising the purchase price closer to market value.  They said they thought I knew they wanted to purchase the house and that they had till the end of the month to close but they would go back to their lender for more money.

Their lender now asked me to see a copy of the amendment to the lease that changed the purchase price. 

Do I need to make a formal amendment or notification?  I did not think I needed to do so but wanted to make sure before I responded to their lender. How much information do I need to give the lender other than that the tenant broke the lease and that I increased the sale price to X?

Thanks