We are a Veteran owned and operated mortgage company.

no, all he gave was a invoice with his company name and address.

If you have the cost segregation done by a reputable company then even if you get audited, you'll have proper support to back up your deductions.Now whether it's worth it - A cost segregation study can be extremely beneficial but its a case by case basis that depends on a multitude of factors.

I would give similar advice to someone that wanted to open a restaurant, landscaping company, hair saloon, etc.  

My company charges an application fee.

There is a company out there right now paying 40% annualized and I know an investor who thinks its great, well yeah its great until you lose it all - as never in the history of mankind has a company been able to pay its investors 40% per year on a continuing basis.

Along with Appfolio, we use Showmojo, Leadsimple, Lowe's and our collections company. 

@Tarik Kafel recommend checking NARM.com for professional and licensed PMCs.Also, here's our copy & paste advice:Encourage you to learn from the mistakes of others - by reading posts here on BiggerPockets about owners not having their expectations met by their current Property Management Company.

I do have owner's company address with me I got it from the county department. 

I had a property in Cleveland (Warrensville Heights) for 4 years and yes, I had to pay for the water/sewer (but not snow plow) and it was in my name, as the utility company billed me directly.But, I had that expense factored into the rent, so I was reimbursed when the rent was paid.