Duplex Under contract - Tenant will not allow access to unit

[Trey Bonner]

Hi BP Fam, 

I am currently under contract for a duplex in Atlanta metro (East Point). During due diligence we were able to access one unit (which has a tenant) once, which happened to be during a time that my contractor was not able to come. We have since ended due diligence and currently working to have my contractor provide a final quote for the rehab. In order to do this, he needs to see the tenant-occupied unit. After requesting access, the seller indicated that we will not be able to access the other unit until our final walk through because the tenant is nonresponsive. The existing lease has a right to access clause as well (I believe 24 hours). 

Is this acceptable? By law, is the seller required to provide access to the property while we are under contract (or is access only required during due diligence)? Considering that the lease has a right to access clause, should/can I be persistent in asking for access? The property definitely needs work which is why I need a finalized quote before moving forward on the purchase. 

Thanks for your thoughts. This is uncharted territory for us.