I have had my Waitrose rewards credit card for about 3 months, but have random times where the card is declined or 'an error has occurred' online even though the app has sent me a valid OTP code. I tried to circumvent this by adding to the Trusted Retailers list via the app. Unfortunately this also has undefined 'an error has occurred' moments. In addition you cant scroll in the Trusted Retail pop-up as no bar is provided. I telephoned Customer Services who told me that it must be my browser and that I should install another. The person clearly had no technical knowledge and was quoting from a 'common problems' faq sheet. I was made to feel like every issue was my error. After being 'fobbed off' for about 30 minutes, I eventually spoke to her manager who promised me a call back from someone with better technical expertise. That was this morning and it is now 17:00. It clearly isnt happening. I will probably go to another provider in the near future as I cannot have random refusals of my card continuing. Looking at previous postings for reviews of NewDay cards (on all review sites), this appears to be a common problem.