One of three things will happen, James.
1--they will validate the debt, and then continue collection efforts.
2--they will either send incomplete validation or none at all, and keep trying to collect anyways.
3--you will hear nothing from them again on this debt, in which case it will probably be sold to another collection agency and the process begins again.
Of these choices, #2 is illegal. The minute they receive your DV request, they are to immediately stop ALL collection efforts until such time that they provide you with the validation of the debt. This means they cant call you asking for money, they cant send you letters demanding payment, they cannot file a lawsuit, they cant do anything. Not until they get you validation. And the law is clear on this--validation is documentation that comes FROM THE ORIGINAL CREDITOR. If they send you back some statement on their letterhead, or something other than the original signed contract, then they did not validate the debt. If they do that, you need to send them a second certified letter and tell them that pursuant to the fdcpa, validation must be original documentation from the original creditor and not their internal paperwork....therefore, they still have not validated the debt and any continuing collection efforts will thus be illegal under federal law.
Also, you asked about a cease and desist letter. The templates that most of us use for DV letters include such a statement. The last one I sent read like this:
You are also hereby informed that you are to communicate with me regarding this matter only in writing, through the mail. No communication related to this matter is to take place by telephone, to any phone number where I may be reached. Should you continue to attempt to contact me by telephone in reference to this matter, it will constitute a violation of the Fair Debt Collection Practices Act and will be met with a summons to appear in court, where you will be promptly sued for violating federal law.
A little strongly worded, perhaps, but the morons I wrote it to didnt seem to understand english very well. In fact, they called after they received that. thats the CA that we are suing for 9 independent violations of the FDCPA within a span of one week.