First flip -Contractor takes way too long

[Marci Stein]

Although I’ve been a landlord many years, I bought my first flip.
the contractor has the key to my house and works on his own. 

I asked him to replace  two bathroom sconces and one kitchen light ,

which he did - 

but told me it took him four hours because there was a wiring problem. 

I said he should have called me if there was a problem 

because I thought that task would take about an hour at most .

now he wants to get paid but it’s not fair to pay him 4  hours without consulting me first .
I am willing to pay for one hour 

please give me your thoughts on what you might do . this is my first flip, thinking it might be my last.!
thank you so much .