Looking for advice in regards to this purchase on a property where I believe the seller may be in fault of breach of contract. Looking to get expert opinions and/or experiences to know how to best proceed.

I went under contract with an out of state property. Went under contract early November. Duplex with a tenant on the top unit. During the earnest period, the tenant complained to the seller that the roof was leaking when it rained hard. She sent a video of it POURING rain inside her unit (far beyond a small leak). The seller had work done on it DURING the earnest period. I still inherited a leaky roof after closing. The seller's response was "The roof already was in bad condition when property went under contract. We had work done to restore the roof to the condition it was in at the time it went under contract." However, I was given NO notification of this work being done during the earnest period. I wasn't made aware of this until the tenant had told me, after I closed on the property. The seller has failed to provide any documentation of any work done. Therefore, I believe the previous owner sent a handyman to the roof to do a shotty, band aid fix. Is this a breach of contract? This may have caused me to back out of the deal had I known about it before closing. However, I've already closed on it, invested $18k in rehab, and still have a roof issue. The inspection company holds strong to their disclaimer of not being responsible for any leaking for the roof, but I'm wondering what the seller is liable for?

Also, there is a significant lean on the top unit. This is very apparent when viewing it from the outside, and when walking inside the house. I'm no inspector, but I couuld definitely see and feel this when I visited the property a couple weeks ago (I bought the property sight unseen). For the selling party - are they breaching contract for not disclosing this information? For the inspection company, I submitted photos to the inspection company, and awaiting their response. However, with their roof disclaimer, I feel they will pull out another similar disclaimer about this. 

Not sure on how much the roof repairs will cost. My contractor says the lean on the building would be an estimated $5,000. I'd imagine the roofing costs would be costly as well.

Is the seller at fault of breach of contract? Do I have means for a lawsuit? And given the above, the costs, and the fact I'm out of state, how would you pursue this? 

Thank you for any insight