@Bob Romano, I am in a similar situation, though not as extreme. My lease states rent is due the 1st, with a 5 day grace period. As soon as the grace period is up, I hit them with a 20% late fee (IL's highest allowable late fee) and I send out the Pay or Quit notice the same day.
I have had a tenant since June 2018 and she has paid on time only once or twice. All other times she pays during the grace period, and this month was her third time paying past the late fee/pay or quit deadline.
I'm not sure what your laws in Rhode Island say you can do, but in Illinois it works the same as what your lawyer is telling you. As long as they pay their rent balance (including late fee), you are stuck with them until the lease is up. Then you can simply just not renew the lease and they will have to leave. If they don't leave, you can evict them because they are staying there without a lease.
My recommendation is increase your late fee. You can't do it on this lease because the $50 is already instituted. But on future leases, get that late fee up to whatever the maximum is that your state will let you.
$50 bucks is cheap.
Hope this helps. Good luck!