Well, I've made a second request - ten days after the original one, to which still no reply - and recevied the customary acknowledgement. After the message is sent the wesbite says that I'll hear from them within 48 hours (hmm..clarly not), while the email acknowledgement says, 'as soon as possible.' If I hear nothing by the end of the week I'll try phoning.
This enquiry concerns bonus points linked to an offer, so there is no need to send them a receipt (the regular points have credited). Twice in the past I have been told I didn't register for such an offer (though I'm 99% sure I did). This time I took a screen capture of the page telling me that I had registered and I attached that to both the original and now this second request. It would help that offers for which we had registered were noted in our profiles, and that the registeration was confimed by email. Other schemes do this.
Once this is solved, I'll chase up the hotel which hasn't recorded any points at all and insisted on giving me a paper receipt rather than the usual, useful pdf file via email.
All this is annoyingly time-consuming. But thanks for everyone's replies.