You can search using Upper (or Lower) when querying a service. You have make sure what you're querying is in the expected case.
For example, I have a field name Comments that contains strings like "Coral" and "coral".
Both of these statements returns all expected records:
lower(Comments) like '%coral%'
upper(Comments) like '%CORAL%'
but this doesn't return any records
lower(Comments) like '%Coral%'