They collect your rent, apply late fees,  deposit your monies into your bank account, market your properties, track expenses, screen your tenants, etc for just a few dollars a month per door.  

So far it has mostly been a deposit of sand.  

I also found out on the day we closed the loan that they have no security deposit either.

Purchase Price:Total: $1,985,000.Deposit: $10,000 (First Deposit) within 3 days, additional $30,000 (Second Deposit) within 30 days.Seller Financing: $297,750 (15%), 5-year term, 20-year amortization, 6% interest.Balance: $1,647,250 to be paid at closing.

The vast majority of lawsuits against Landlords are for wrongful eviction, security deposit disputes, and Fair Housing Violations.

Then you will have a 10ish min quick walk through the property and if his pictures matches the reality and you don't see anything abnormal, then after you sign with him assignment agreement and you put nonrefundable deposit and close in about whatever days you agreed on(usually up to 10).  

A cash deposit of $10,000 was required,, then a $300 a month payment till it was paid in full.

They are yet to pay the deposit.

Collect deposit?

For example, I often see Buyers purchase property thinking there is a $1,000 deposit but then the tenant claims it was $2,000 because they paid the last month's rent.