it's legal to call your neighbor and ask questions about you as far as where you live, where you work, and what your personal telephone number is.
it's also perfectly legal for any person to call your phone number and ask for a person who you don't know, whose name is hard to pronounce, or who they think might live with you. your response should be that you don't have any idea who that person is. if the calls drive you nuts, all you can do is exactly what you did do. call the company and tell them. don't be rude no matter how stupid the company rep is.. because the last thing you need is a dumb rep who doesn't remove the number from the computer list thing that is calling you. better to kill it kindly and get what you want, freedom from endless ringing.
if your payment is not accepted, it does not get you off the hook. if your payments are refused, put your payments in a shoebox until you have enough to pay it off. that's the smart thing to do. by then, maybe the debt collector will settle for less when paid in full- when if they had accepted payments you probably would have paid in full.
while you're at it.. record your phone conversations. if they swear at you, call you names, or threaten things they can't or don't intend to do.. then you can sue. debt collectors can imply you are a deadbeat, but they can't say it. they try to make you feel bad because it gets you to pay. in the end, if you aren't paying they really don't want to call you. they have to because it's their job, and they don't make much money, so they do what they're told to do. sometimes they find it funny how upset people get, or how people threaten to call a cop, or people threaten to call the BBB, or they threaten to sue. debt collectors know suing them is an empty threat, it would be easier to pay the bill than to sue. the calls continue. "do not call me on this number" is what the response should be.
keep in mind, it is a violation of the fdcpa to cause a consumer to incur more debt in the collection of a debt. overdrafts are a concern, calling you on your cell phone, calls at work that piss your boss off. these are things you need to tell them to not do as they happen. you are 1 in about 400 calls they make everyday. you aren't that important. don't give them a reason to want to harrass you by acting crazy on the phone.