One week between Christmas and New Year may be understandable and I don't begrudge the men the time off. But we are talking about a three week period here not just one week.
As far as I understand a contract is a legal document. Both sides read and agree all the clauses before signing, therefore either the Borough Council have agreed to this clause leaving residents with no dustbin emptying for three weeks, or Biffa are breaking the terms of the contract and the council should take action against them.