Misleading advertisement: Free 5-weeks Cover is actually 4 weeks, after a week's wait

We had the free 5-weeks trial, that was offered to us when we picked up an 11 year old deaf cat from a local sanctuary, where she was declared healthy apart from a hip issue by their vet.
As any responsible pet owner would do, we immediately signed her up with a local vet (as requested by Agria per mail) and had a general health check, 5 days after the adoption (and start of insurance). During this check also blood was taken, because she's an older cat. Agria will say it is common practice for insurers to have some form of "wait period". They desperately want to distinguish themselves from other insurers.... but not that much.
The blood results came back a few days later (7 days after we our insurance policy with Agria started) and it showed there was possibly an issue with her kidneys and a urine sample & CT scan were advised. I called Agria to ask if this would be covered under our policy and was advised this was no problem, it did come with an excess of £120.
We did not claim for the blood check, but for the urine sample & CT scan the week after (13 days after policy started). We were happy with Agria, so we also went for a new policy starting after our trial. However, after nearly 2 weeks I submitted the claim, I received a letter to say they would not pay out, due to it falling within the 7 days of cover of the policy.
- Firstly, this is strange to offer a free trial of 5 weeks and then not to cover anything in the first 7 days.
- Secondly, our claim was from after the first 7 days of cover. The dispute is now that they say we had prior knowledge of the issue, which we didn’t of course.
- We received a note from Agria in the mail to say "your pet is now covered", but clearly this is misleading because she wasn't
- We received a note from Agria wanted our vet details, but failed to mention that you shouldn't find one in the first 7 days.
- Lastly, they have bombarded me via texts, e-mails and letters to sign up for a new policy, but for the claim they use a letter to respond that takes 2 weeks to be sent.

Luckily our cat has fully recovered, because the infection has disappeared after a few antibiotics’ injections and another urine sample test.
However, we cancelled our policy with Agria and found another more reliable insurer, not that we would get the money paid out, but rather a company more trustworthy. The problem is that obviously any future issues with kidneys will not be covered by any insurer as it's it'll be listed a "pre-existing". Thank you Agria! And thanks to Agria, I’ll think twice before “doing the good thing” and get a pet from a sanctuary, because of the struggle to get a proper insurer.