Duration Windows

I ordered a cill with the painfully unhelpful after sales team at Duration Windows, whose responses to my request were short and uninformative, it was like drawing blood out of a stone. I wasn't provided an invoice or a receipt or any confirmation of purchase with them at all. I called to ask for a proof of purchase and they said there wasn't one...?! After receiving completely the wrong size, which could have been avoided if I knew what I was paying for with an itemised receipt/invoice! I then had the misfortune of dealing with some very bad attitudes and incompetent people in the after sales team again, who told me that I need to write it in an email, so I did and still haven't heard anything back. Judging by the previous complaints it seems that they need to question their after sales team.