Distilling is the process where the liquid(usualy water + barely/potatoe skins etc and some other stuff even crude oil) is boiled. the vapour is the fed along pipes and cooled. when the vapour cools it reverts to it's natural form(a liquid again) and is collected, thus you have a liquid with all the impurites removed. Distilled water. for oil they use different cooling temps to get petrol/gasoline, parrafin/ kerrosine, the diferent grades of engine oil, rocket fuel(some types only), etc. No comments about a scotsman know ing the distillling process please, the Irish and the American red necks and hill billys no better about "the 'shine".
De-Ionisation comes from when the water is passed through a filter that removes the positvley and negativly charged ions.
I'd say take the stuff back and change it.