Many people do not like to switch at one brand to another.
switches at
switch from
switching on
No correction required
The correct preposition that should be used is 'switch from'.
If no one switched from Gurumath to Edustar at the beginning of August and atleast one person switched to Gurumath at the beginning of August, what is the minimum number of people who should have switched out of Matonline at the beginning of August?