2. A comma before "but."
3. Not really. It sounds (to me) like someone is calling you and saying "Hey, remember to keep in touch with your clients."
I still enjoy taking calls from our customers so we can keep in touch.
I still take calls from our customers, so I can stay in touch.
(It sounds a bit social, though. After the big sale, you became friendly. Otherwise, why would they call you?)
Student or Learner