[mothered]

In my experience I get a lot further by calling reps since you are able to put the reps on the ropes, and will apply some pressure to help move things along. 

In terms of addressing the claim there and then, a phone call Is certainly more effective than shooting off emails.

The only downside Is, communication Is Instant, hence you'd need to Immediately think of the most appropriate reply. One wrong move can have an Impact on the claim.