UK Property Manager is A MESS - Need a London Lettings Agent

My friend's letting agent is terrible. It's a small company that has done the following:

1. placed hidden fees on to services for the property

2. let the lease expire without getting the agent to sign a new lease

3. cancel meetings after pretending to be sick

4. Constantly ignores his texts and calls

I believe this to be a material breach of the property management agreement. Is that so? Also, are there any good lettings agents from a medium to large estate agent's based in London?