Who pays rent upon delivery of the home before the official end date of the lease agreement?

Questioner

I rented a house until September 15th. The new tenants asked if they could move in earlier. In consultation with the landlord, the delivery and handover of the keys took place on September 8th. I was under the impression that the landlord would pay me back the rent from September 8th. However, he only does so from September 16th. The new tenants also pay from September 16th. It seems reasonable to me that the tenants pay me back the 8 days' rent. It concerns a rent of 1700 per month, so it is a substantial amount. I would like to hear your opinion

Lawyer

It is the landlord who you should contact about this, as he has enriched himself through the act.