Typical to take first payment?

[James Fife]

I recently bought and rented my first rental investment property. I hired a property manager that my real estate agent recommended to me. I interviewed the property manager and it seemed like a good fit. The rental now has a tenant and this is when I reached out to ask for payment. I was told that the first month's rent is for themselves and then they also charge 10% property management fees on each additional month's rent. I was aware of the 10% management fee but not the whole taking my entire first month's rent. I reviewed my contract and I did find it in there so that's a lesson on me. However, I would like to know how typical this is since I have never heard of it before? Is this a common practice? I'm frustrated because that just shot up my management fee to 21.7% for the year and am now cash negative because of it and also frustrated at myself for not catching it earlier. This is also a new build so very little maintenance will even need to be done with it. They have not been easy to communicate with and are slow to respond but now I feel obligated to continue with them since they already took the first month's rent. He also pocketed the two application fees. Please share you experiences and thoughts.