Delivery lorries not being able to access Glyn Avenue

Delivery driver coming to deliver hardcore was not able to access glyn avenue due to the six form from the girls school blocking the entire lenght of road. Even though the head of year was summoned to try and get the vehicles removed she said she couldn't do anything. Can I have a contact number please, one so that I can get the vehicles removed and two to claim compensation as I now have to pay for the hardcore to be taken back. This is not the first time the avenue has been blocked we had to go 1 month because the rubbish couldn't be collected. I have sent this e-mail because I am so so so so cross!!!!