If you had cold-called by a paving contractor there is no surety whether they were genuine or not.
Many contractors want to disperse their cards so that more people know them and contact them when needed.
If you have such a card, call them on given number before you agree to any work being done on the patio, driveway, or porch.Look at their previous workA good trustworthy low voltage outdoor lighting expert should be able to show you block paving and lighting work that they have carried out before.
If they cannot demonstrate you any portfolio they have done why take the chance.
If they do show you previous works then go and have a look.
Make sure that the backyard pavers they show you were actually installed by them.