Disclaimer: I'm from Russia, English is not my first language, sorry for weird phrasing. TL;DR at the bottom of the post 

Me and my bf rent a studio apartment in an apartment building. Our next door neighbor is a really old lady. She barely walks and is practically deaf. 

Every other day she comes to our apartment door for whatever help she might need: to open a jar or a bottle, to change a light bulb etc. Sometimes she asks us to buy her something in a grocery store (we never take any money from her even though she tries to pay us back). She is really nice and it's never been a problem really. 

The only actual issue I have with her is the way she knocks on our door. We don't have a doorbell, so she takes her keys and knocks violently on our keyhole. Sometimes she comes to us early in the morning on the weekends, and waking up to this clanging is awful. Sometimes she needs something while one of us is in the shower or while we are having sex or whatever, and she doesn't stop knocking until we open the door. She doesn't stop knocking even if we yell asking her to wait for a sec, due to her lack of hearing.

 Our landlord told us that she doesn't have any relatives or friends in the city, so she can't call anyone else to help her I guess. I suspect that she might have some sort of a social worker visit her from time to time (her apartment is really clean and her fridge is always full even though she barely walks etc), but I have never seen them. I don't mind helping her but all this knocking drives me insane. We tried asking her to stop knocking so vigorously, but she forgets things and every time it's the same thing.

Sometimes I can't help but think what happens if we stop answering the door at all. She might start going to other people for help, but our other next door neighbor is really shady and weird, other people who live on our floor are also quite old, and I don't think she'll go on other floors. I'm heavily guilt-tripped even thinking about stopping helping her, but sometimes I feel like she's using us for doing even the smallest things and she must know that we can't say no to her 

So, would we be assholes if we stopped answering the door for this lady?

TL;DR: Our next door neighbor always comes to us for help, she knocks on the door as if she wants to wake up the Satan himself. WIBTA if I started ignoring her? 