Can micro- and macro-level theories be combined?

Microtheory and macrotheory can definitely be combined. In fact, macro and micro approaches are complementary methods; understanding one will lead to a better understanding of the other. 

Let's say microtheory looks at how individual behaviors related to smartphones affect productivity and relationships in the workplace. Microtheorists use observational methods, interviews, and record-keeping to inform their conclusions. Macrotheory looks at whether there have been any changes in workplace socialization since the rise of smartphones. Macrotheorists use surveys, raw data, and existing research to draw conclusions. 

A microtheorist might conclude that those who spend the most time on their smartphones are more productive while at work, but less socially bonded with their coworkers. Macrotheorists conclude that, given the data from 20 years ago, productivity is at an all-time high, but social bonding in the workplace is at an all-time low. The microtheorist can support his or her findings with the macrotheorist's findings, and vice versa.