Barclaycard credit limit reduced from £9000 to £750 without notice. Credit report from all 3 agencies are OK. Can't find out why this has happened. Can you suggest what should I do next?

L'auteur voit sa limite de crédit réduite sans explication claire de la part de Barclaycard, malgré des rapports de crédit propres

Hey, I could use some help with my Barclaycard situation. I’ve been a self-employed site manager for a while now, and I’ve had a Barclaycard credit card for years. I usually spend between £1,300–£1,800 a month on it, and over time, my credit limit went up to £9,000. But about four weeks ago, on a Saturday, they suddenly dropped my limit to £750. I called customer service, and they said it was due to something reported by a credit reference agency—Experian, Equifax, or TransUnion. So I checked with all three and pulled my credit reports. Everything came back clean. I even contacted them directly, and they confirmed there’s nothing on my report that should’ve caused this. I went back to Barclaycard, and they keep saying the same thing: it was based on a credit agency report. But they won’t give any clear answers. I’ve even spoken to a supervisor, who passed the issue on to some “higher team,” but I’m still just getting vague replies with no real explanation. On January 4th, I bought a Sony camera from the Sony store online using PayPal Credit. My PayPal limit is £3,200, and I used £1,200 of it for the camera and accessories. Someone from TransUnion said that shouldn’t have had any effect, since it’s being paid off monthly and I used less than 50% of the limit. Now I’m stuck. Barclaycard won’t budge, and I have no idea what to do next. My credit score is 992, so I really don’t get why this is happening.