Property Management Maintenance and Flat rate vendors

[Gen Young]

Hi everyone,

I have a couple properties managed by a prop management that charges me a flat rate fee monthly. I seem to constantly have repairs for an 8 year old home (which the tenant does not even pay on time), including leaking faucets, fallen fences caused by overgrown trees falling, broken exhaust fans, etc. Most recently, some part on the heater/ac broke which they are charging me almost $400 for. I asked for invoice from the vendor but she said it's a flat rate and if I wanted an "estimate" it would be an extra $65 charge. I'm having trouble seeing how this costs $400 when the part is $100 at Home Depot. She said if I wanted a different vendor, there would be another fee. Just wanted to check if this is normal? I'm pretty new to this so any advice would be great. Thanks!