How many strikes before switching property management companies?

[Graham Watts]

After a few months with a property management company, they have made a few mistakes: 

- Forgot to resolve a broken item in the condo for the tenant, with no communication about the fix/progress for over 2 months

- Miscommunicated rules of the lease to the tenant

We’ve also received feedback from our tenant that they aren’t very happy with the tenant-side service. 

How should we decide when to start looking to switch management companies? Their fee is 9% of the monthly rent, plus 50% of the first months rent per new lease signed.

Thanks in advance for any advice!