You're only worth your last achievement here.
Management is very unfeeling here. Dare I say, misguided, but mostly in how they deal with employees. The clients seem to get their needs dealt with, but if The Boss, and we know who that is, has a bad weekend, he'll be cutting you to shreds with his words for no reason at all. There's no possibility of advancement here. You work one role and when it runs out, you're out.
As long as the client needs the service, you'll be happy
Tying jobs to one client means you'll only be happy for a year tops.