Neighbours — Dog barking noise

Hi Sir/madam,
My old-age parents living in a small Apartment for more than 20years.Few years back a new family with a dog moved to this Apartment and they ll not tie the dog, leave it open and bark all the time on everyone who comes entering the apartment and we are very close to them my parents cannot sleep they are patients.We talked to the dog owner but no response they didn't care about us. please do the needful action on this ASAP.