how to hand over a rented office and avoid paying rent if denied access by landlord

A company has rented a small office in a business center, but has been unable to pay the rent for a few months since the COVID-19 lockdown.

The business center has locked up the office, preventing access and usage, but continues to accrue the new unpaid rents as being due even though the company has no access to use the premises. Is this legal?

The lease mentions that the landlord is allowed to lock up the office in case of late payments, but I had in mind that was illegal, hence that this clause was invalid, and that the company should have access to the office and to retrieve its belonging from there.

Thanks,

E.