Accounts are mismanaged, often a very stark break in communication between this 3rd party and the client account. Managers often have no idea what the client is doing and vice versa.
Broken promises regarding bonuses, this company will alter sales goals and KPIs to avoid paying bonuses at all costs, even going so far as to purposefully skew data.
The company's ultimate goal is to please the client, not actually accomplish the goals the client sets out for them. Often they will hide issues from the client, and live by the adage that there isn't a problem until someone brings it up (then that person or group becomes the problem, and is gotten rid of instead of addressing the actual issues).