Tenant complaint - suggestions for responding back

[Raman Bindlish]

Hello to experienced landlords,  I just had my first turnover in the duplex and I got following complaint from the tenant. I would appreciate how best to respond to this.  Can this be trouble if I just tell them that they inspected the place before signing the lease? Is there any law for minimum width for stairway? 

"A huge issue that we had moving in was learning that the box springs for our beds will not fit up the stairway- not even the smaller size for kids beds. Had I known this, I would not have applied to rent for this house. Leo had to design custom platforms, purchase and cut the lumber, take it up to the designated bedroom and build all of us new mattress supports. This was an ordeal, to say the least. I feel that this is something we should be compensated for- at the very least, we should be reimbursed for the materials we had to purchase. (I will provide receipts to show the cost of the lumber, etc.) It took Leo two hours to put together each bed- and that is not taking into consideration the time it took him to measure, design, and make multiple trips to the hardware store. I think it's safe to say that most people would not have had the skills or backround required to make such adjustments, in order to live in this house. That staircase is definitely not up to code.  "