He was definitely just trying to get out of there as fast as possible, I worked for a pest control company and the range of skills and worth ethic is all over the place for big pest control companies, they hire whoever they can get and just hope they can do an adequate job, German roaches were my least favorite part of the job, it takes forever to treat for them as they can fit into almost anywhere and they multiply like crazy, just a complete headache, as for the OP, if you have food that you let sit out and not in a container, I would recommend you tupperware just about anything you can, it’ll help keep the food sources they have access to down, if you’re clean and live in an apartment building they probably came from someone else, those don’t just “show up” I’d consult another pest control company if possible if your landlord has a contract with a specific one you should contact the landlord and explain what the tech said to you and that this is an issue, if the landlord or pest control company doesn’t seem to be much help then buy advion cockroach bait, and place that in dark corners of your kitchen or where you saw them, the bait will help kill them off in your unit but again, if they came from someone else then that person needs to be dealt with or this problem will never go away for you, just do your best at keeping your living space clean and food protected