Everything I buy I tape the receipt to the electrical cord or directly to the item, clothes I put the receipt into my 'receipt drawer' they expect you to lose the receipt and just chuck an item away
I often take things back that have not lived up to their promise, be firm and usually you get something, clothes that don't wash well is my biggest pet hate, 'they shrink they go back' even if its 11 months later.... I might have only worn it twice.
If aldi offer a 2yr warrantee them keep the receipt and any other marketing material that states the warrantee