Call centers - possible off shore call centers.

Please note that this number is given as contact information for Nextel, UPS, Microsoft, and a few others (most often mumbled so low can barely discern who they are supposed to be calling on behalf of). The caller(s) have thick mid-eastern accents and very rarely polite.

They mask their numbers at all times coming in as external caller unknown or using Skype's free lines along with other numbers that don't often match the company's they claim to represent.