New tenants fist check NSF, second month rent late and pet violation

[Cory Adams]

Fellow BPers how might you handle this situation:

a young couple had good references and rented a unit from me.  First check couldn't deposit as it was a starter check (not their fault).  They provided a second check returned NSF.  They paid cash to me after that.  

Second month of rent is July and I have not received a check.  I was going to use that as an opportunity to use erentpayment.com or another service but now I'm thinking eviction as I found out from the other renter, within the duplex that this couple has a pet and that this dog has been defecating in the small common area between the 2 units (right by the front door).  They specifically told me a month ago that they did not have pets and had no intent on getting pets.  The lease reflects this.

I emailed them about the lease violation and the late rent.  I asked that they call me and I left voice mail.  If I do not hear from them by tomorrow I am planning on hand delivering a default notice outlining my remedies per the lease and the lease violations while giving them 24 hours to try to reach an agreement with me.  The lease states that after that I may provide them a notice of eviction which gives them 24 hours to vacate the property.  It's a standard TX lease.

What would you do?