Praise be to Allah.
The basic principle is that prayers should be offered in congregation in the mosque, where the call is given. It is permissible to pray in congregation in the workplace if the workers going to the mosque will lead to the work being affected. This has been discussed in the answer to question no. 74978
With regard to praying Jumu‘ah, it is more important and the obligation is more emphatic; it is not permissible to miss it except within very strict guidelines, such as the risk of damage or harm, or if there is an interest to be served for the Muslims, such as dealing with emergencies in hospitals, and the like. This has been discussed in the answer to question no. 36530
Based on that, you have to go to Jumu‘ah, and advise the owner of the apartments and explain that it is not permissible to stay away from Jumu‘ah, and he will not be harmed by the loss of a few customers; many customers, if they find the building locked, will come back after the prayer. You should go out to Jumu‘ah just before the adhaan, and go to a nearby mosque where the khutbah is not too long.
And Allah knows best.