Inherited Tenant won't communicate, need help!

[Samantha Klein]

Hi, I bought a property last week and inherited a single woman in her early 20s, she's renting a 1 bedroom apartment for only $375, market rent is $475-500. I'm stuck with her right now as she signed a 1 year lease April 1st. Anyway, I have been trying to reach out to her in regards to how she plans on paying rent and she needs to know who and where to send it, she was paying the previous owner via ACH and I would rather just get a check or cash. The tenant won't answer phone calls, her door, and I texted her last night and asking if this was the tenant and she said yes, who is this? I told her who I was and no reply back. Should I send her a formal letter introducing myself and explaining how rent needs to be paid from now on?