The EU is rightly furious that AZ have reneged on their contractual obligations, as anyone else would be in the same situation. The EU paid €336 million to AZ as an investment in their production facilities, in order to avoid these kinds of supply issues. That's entirely separate from the price they're paying for the vaccines themselves.
AZ are only reducing supply to the EU, and are doing so by 60%. When Pfizer had to delay their supply, they did it proportionally, which is the fair and responsible thing to do. It's hardly surprising that the EU is now trying to make up the shortfall. The UK would do exactly the same thing if the shoe was on the other foot, in fact any country would. This is not an attack on the UK.
As for the rollout, that is the responsibility of each member state, not the EU. Some countries have done very well, like Denmark, other like France are much slower. This is partly because they wanted to wait for the AZ supplies for logistical and cost reasons. That was France's call, not the EU's.
There's a lot of smugness here and a great desire to stick the boot into the EU, without looking at the bigger picture. The EU is not perfect, but some of the comments here are ridiculous.