No printing of invoices, but where is my emailed invoice?

Can someone please explain how the invoicing at your Canal Walk iStore works?

I visited the store on 15 September - it has great stock and the person assisting me was very helpful.

However, when the assistant rang up my purchase, first she wanted my phone number. This was to try and find me on the system, which she did not manage (although I have purchased at an iStore before). Then she asked for my email address, and when I asked why, she said it was to send me the invoice. I gave my email address reluctantly and left only with a credit card slip as my proof of purchase.

I waited for the invoice which has to date not arrived (yes, I did check my spam folder). But, on 21 Setpember, I received a "iStore Customer Service Survey" email for the purchase I had made! So, my correct email was definitely captured on 15 September but where is my invoice?

I never signed up to receive surveys from you and I was not happy to give my contact details to you - especially for a small purchase of a screen protector. But now you are spamming me with a survey.

Can someone please arrange to email my invoice to me as promised, or do I need to insist on a printed invoice?