Neighbors child obsessed with my child?

I feel like my neighbors child is obsessed with coming over ALL the time. During the week as soon as school ends the door bell rings. Coming home from the store the bell rings. If we tell the child to go home because we need family time an hour later they will be checking in. If we tell them our child is grounded or sick for a few days the child checks every day several times a day to see if they can play again. We have spoken to there parents about it however they do not have set rules for there child and do pay attention to what she is doing as long as it does not bother them. As a side note I also feel when the child visits all rules go out the window they look for things and stuff to get into which my child does not normally do and knows better. We have attempted to explain these rules to both children however it seems to not matter over and over again going into the garage looking for things to play with and our personal office space. I do not see a harm in them hanging out, however Friday afternoon to Sunday night seems excessive politely we will insinuate the child go home and check in and the answer is always "no I am ok my parents know where I am" we will then insinuate the child leave because we need family time upon coming back the child usually be waiting in the drive way or show up a min after ringing the doorbell . Also the child came over christmas day from 9am to 9pm they only way they finally went home is when I insisted they leave. Can anyone relate to this?