3rd April 2016 From Philippines,
In case it goes into a legal issue,you have proof of asking for educational documents back.
The company is aware that retaining such documents is wrong and written demands leaves behind a documentary trail which they will want to avoid.
Text message etc has limited effect-after all it can be deleted from recipients phone.
3rd April 2016 From India, Pune
4th April 2016 From India, Bangalore