Before I began living in an apartment complex, I lived in converted apartments in old houses. The owners were the landlords and they did ALL the work except for plumbers and electricians. They had day jobs and did whatever work needed to be done in the evenings and on week-ends which included lawn care and snow removal.
I guess if you want an income from property and you don't want to do the work yourself, you are just going to have to trust those you hire to do it for you - but I sure do hope you do a good job of vetting else what's the point?
Maybe you shouldn't be in the rental business at this point in your life if you can't trust the people you hire to do what you want them to do at the price you want them to do it. If you aren't going to do the actual work yourself, you should still be closely monitoring the people you hire.
It would seem that the house wasn't up to code and they found more problems as they went along. It happens. Just watch all those fixer upper programs on HGTV and DIY network. Some pretty costly unforeseen problems crop up all the time; e.g. foundation issues, plumbing, replacement of floor joists and floors, roofing, etc.