Have experienced exactly the same problem with mine about a week ago! Very disappointed, as the unit is less than 10 months old & has seen relatively little use since purchase. Sadly, ALDI are betraying their German roots & now mostly sourcing their tools & electrical appliances from China, which, from personal experience, is a country not renowned for quality assembly of products, no matter how nice they may appear on the outside! All credit for it being under a 3 year warranty, but it's probably going to cost at least £10.00 to send the thing back & will the same fault eventually manifest itself again? Much as I hate scrapping almost new equipment, this might be the cheapest option in the long run, although technically (under the Sale of Goods Acts), my contract is with the shop that sold it & hence they should be responsible for getting it repaired or replaced. As I have the receipt, I shall try this & see how the local store responds, if they won't get it fixed, then I'll demand that they refund me the full purchase price instead. Since it is likely that your own kettle will be of a similar age, if you have also kept a proof of purchase, perhaps it might be worth you doing the same (there are a number of good UK websites that give official advice on your legal rights with regard to fitness for purpose, expected longevity of service & warranty information). Armed with that, you should be able to parry aside any awkward store manager if he or she tries not to "play ball"!
Instech
February 2012