Should I send a Cease and desist letter

[Fedral Reserve]

I have two investment properties that are currently going through the "Short Sale" process or if not going to foreclosure.They both have 1st and 2nd mortgages on them. both properties are in Florida.
The 1st and 2nd Mortgages on the two properties are with the same lender (Countrywide).
I received A letter from Real Time Resolutions INC regarding one of the properties on 9/17/09 stating that the collection duties associated with the 2nd Mortgage had been transferred to them from Countrywide Effective 8/31/09. and that all payments should be made directly to Real Time Resolutions. In there Letter it states that they are a debt collector. I also received another letter from them regarding the other property on 10/26/09 saying the same thing with an effective date of 10/5/09.
I sent a Debt validation Letter for both of the properties to real Time Resolutions giving them 30 days to respond. I sent a 2nd letter 30 days later stating that they have not responded to my previous request.
On one of the properties they have only sent a copy of the 2nd mortgage with countrywide and nothing else. I have heard nothing back with regards to the other property.
Both the 1st and 2nd letters have gone way past their 30 days response time for them.
We have had several phone calls from them ,but have not picked up the phone as of yet.

Should I now send them a Cease and Desist letter as my next step, Is there any FDCPA violations I can get them for at this stage.