Inherited tenant problems

[Luke Carl]

Tenant was extremely unhappy last month, which was my fIrst month as owner, when I imformed then that their lease says there rent is $570 as opposed to the $520 they’ve been paying for 8 years. I called today (The 4th) to inform them that rent is due on the 1st and she said “it’s in the mail” and hung up on me. This tenant had been month to month for over 2 years. I’ve never done an eviction or had to ask anyone to leave. What do I do? Keep them? Get them out? Up and coming C neighborhood duplex. The other side pays $600.