one good thing about renting in america is we have tenant / landlord/ maintenance/ public housing/ renting laws. one of them being when a tenant reports a problem with something in the apartments need fixing, the repairing department or landlord or manager of the apartments .....must.... ask whether the tenant gives permission for the repair people to enter. (there are repair forms with this right on it that if the tenant at any time has stated yes, that box automatically gets checked )

my first suggestion is to check with your managers or landlords to find out whether at any time you stated it was ok for them to enter. even if it was back when you first moved in if you stated yes then they have that right to do do........until..... you put in writing you no longer give this permission to enter and give the form to the manager\landlord (your landlord or manager can look in your file they keep on tenants and let you know if and when you gave permission and how to rescind that permission.

if it turns out you did not give permission each managers/ landlord has to give the tenants in writing the complaint procedures and where with the nearest authority on renting laws to your location is. you can ten put in writing this violation of tenant landlord manager laws.

But you may also reread your lease, most renting leases in america contain a clause that states how many hours prior notice to enter is given and under what circumstances they do have a right to enter without notice... usually this is things like emergency repairs anywhere in the building including the stated apartment that would result in great damage if , suspicion of crimes being committed on the property, or if the complex/ apartment building is HUD/Section 8 they are required to do repairs with in a certain amount of time regardless.

my point there are many reasons here in america why a repair crew can enter an apartment with out notice. so before taking a knife to someone you might want to first check things out and make sure whats what in your lease, and laws in your area.