On 10 October 2019, I renewed my legacy 55/10 contract for another year at the same price. Today 08 November 2019 (my new 1yr contract start date), I have noticed that my current speeds indicate that my service has dropped to 40/10.
I have tried to resolve the matter over the phone, but your representative had never heard of your legacy 55/10 service, and managed to cut me off when transferring me to someone who could possibly help.
I've just had a look and everything is fine with the product and profile you're one but you have a phone fault on the line (an unbalanced cable) that is likely causing the problems you're experiencing. I've raised this here and we should have an update on Monday at some point.