Legal questions about residential rental?

Questioner

our son is leaving home. studying at the TU in Eindhoven. Anti-squat living seems interesting to him. Choice falls on company X. Registration fee 15 euros paid on 16 aug. Then all requested documents delivered via internet. Including guarantee by us his parents. Son is invited on 29/8 to visit a property in Boxtel on 30/8 and compete. The invitation includes an invoice in which unexpected 310 euros contract costs, 40 euros administration costs and 75 euros for a fire safety package are listed in addition to a high deposit, the first month's rent and the first month's additional service costs. Questions: Are costs that have not been specified in advance by the entrepreneur X or for which there is no prior notice on their website still unlawful? We have decided not to continue with Interveste, can we force them to delete the account including all documents? with thanks and regards,

Lawyer

Are these additional costs not mentioned somewhere in the terms and conditions on the site or in the papers sent to you (the exact price does not have to be included, but they must be implemented)