Quiting through text isn’t that professional either so maybe give the manager a call since you have their number, or email the store?

I just heard my manager dealing with something similar. She is trying to fire a partner who has been a problem since day one and head office told her that texting is not acceptable communication for issues like that. She had to call the partner multiple times. I think they are ignoring your text and waiting to see if you will actually call them. I think it’s totally unprofessional on your part to text your resignation but they should be mature enough to call you to talk about it or text you back saying it’s not appropriate.