To expect company to honour discount advertised?

[SaveBandit]

I was going to buy a big item costing over £500. On their website they advertise 5% discount which I was pleased about. After I looked at their website an ad popped up on my Facebook page advertising a higher discount. I followed the link and could only find the code for 5% so messaged the company on facebook to ask if they were still offering the higher discount. They replied saying this was not available and they were unable to offer more. I replied with a screenshot of the ad and asked if they could honour this as it showed up on my phone and computer today. They just replied saying they were unable to do it. I searched for another company and again this company came up in the search results in the ads section saying they offer the higher discount.

Is this normal? Completely prepared to be told I'm being unreasonable but wondering if this is false advertising?

It could be an old discount code?

Yes invitation to treat. They don’t have to honour it.

No it’s not binding, as pp said it’s an invitation to treat and the seller does not need to honour it. If you’re pleased with the 5% I’d take that

Ok thank you for the replies. It says on the google search that it expires 29/3/18.

They have messaged me again asking what product I was planning on purchasing with discount so I replied with the one I wanted and they said that they would offer the higher discount this time and will ensure all the ads offering this are removed. So it's worked out quite well really!