"My neighbours continue to feed them with dog food"
I had a similar problem. I fought your war. Tried everything Amazon had to get rid of the critters, with limited success. Begged for help online. You need to attack the source, which is the neighbour feeding them. It takes a subtle kind of crazy to feed local feral animals so don't expect rational thought from them. You must make them feel your pain.
1. For small areas of your property you want to keep the foxes out of, spread pinecones & broken sea shells (eBay helps you here).
2. Take the neighbour's dog food bowls, empty them by spreading their contents near their front door bushes. Makes it harder for the foxes to eat & they poop near the bushes.
3. Take whichever type urine attracted the foxes, buy lots and lots more and spread it near the neighbour's front door. Let neighbours think the foxes are peeing near their house. (In my case this didn't work, read on)
4. If this does not work, time to fight dirty. Does your town have an online portal? Look for one for filing complaints about animals. Fill it out - use a fake name & disposable email address. Refer to your neighbour as being "across the street" to throw them off track. Complain about the foxes & give the address of the neighbour and explain they're feeding them. Read your town's laws carefully so you know what to properly accuse them of. Often this results on a 30-day probationary period for the neighbor as they're being watched by the town.
5. If this does not get the results you want, fight really dirty. I filled out three online forms over two days. Used three email addresses & different computers with different IP addresses. Using broken English I complained "the animels are uncleen and violate my religion", on another "neighbour keeps them as pets and feeds them and one bite little child HELP HELP!". This will get them a visit from officials. In my case, this did finally get the neighbours to stop feeding the local feral animals, but it was too late for them...
As I wrote, it takes a subtle kind of crazy to feed feral animals. When the officials visited my neighbour & they opened the door, they were met by a slap in the face of urine and feces stench coming from inside the house (this is why they didn't smell the wolf urine I spread). This is actually very common from people feeding feral animals - they had a dog & two cats that they never let leave the house! The town cited them for a health violations & the house faced being condemned.
It gets better - they were renting & the town notified the landlord, who ended up evicting them! The landlord had to completely gut the house, including removing all the carpets & interior walls, to get rid of the stench and make it habitable. The construction workers had to wear hazmat suits.
In short, you're a computer geek, be one! Read up on your town's laws, familiarize yourself with their portal and what to fill out. Take the fight to the neighbour. Good luck!