How do i go about firing a property manager?

i'm paying a PM 8% to cut checks after the 20th. the tenants have let the front yard go, and he has done nothing to fix the situation. there are outstanding fines from the HOA (dating back to april) which he was supposed to have paid (and even deducted money from my rent to pay them!). now my money is somewhere, the fines are still outstanding, he was supposed to have hired a gardener weeks ago, and he hasn't responded to my heated e-mail i sent over a week ago. While he hasn't explicitly broken his contract, he is doing a piss poor job, and i'm doing almost all of the work myself. i need him gone, how can i do it without being on the hook for the rest of the contract?