Product: Debt collection

I received the attached letter by US mail, from Firstsource Advantage LLC, dated XX/XX/scrub>XXXX XXXX XXXX  regarding a debt they are trying to collect. They identified the debt as XXXX XXXX in the amount of {$10000.00}. I do not have any responsibility for the debt they are trying to collect. 

I sent a multi-page certified debt verification letter to Firstsource Advantage, by Certified US Mail on XX/XX/scrub>XXXX XXXX XXXX also attached. I sent the letter to the following return address, as evidenced by the Certified Mail Receipt Ive enclosed, instead of the po box directed in the letter they sent me as po box es do not accept Certified Mail. : Firstsource Advantage XXXX XXXX XXXX XXXX XXXX, NY XXXX Today is XX/XX/XXXXXXXX XXXX XXXX  almost 2 weeks from the date I sent the Certified Letter from the post office in XXXX XXXX Illinois XXXX. USPS online tracking shows the letter is in limbo. 

I want to ensure that Firstsource Advantage receives my Certified Letter and provides ALL the debt verification information I requested as follows : If they have good reason to believe that I am responsible for this debt, please provide the following documents to me by mail, at the above address, showing my responsibility, if any, including but not limited to : A copy of the application for credit that details exactly what debt you are trying to collect A signed contract proving this debt belongs to me A copy of the cardholder agreement and any amendments, showing the terms of the contract ( interest rate, late fees, etc. ) Monthly statements from the last time there was a XXXX balance, up to the final statement, showing ALL charges, payments, credits, etc. to compare with the cardholder agreement and verify the authenticity of the charges The name and address of the original creditor, the account number used by that creditor, the amount owed to that creditor when you purchased the debt, and how that amount was calculated Verification and documentation that there is a valid basis for claiming that I am required to pay the debt to Firstsource Advantage. Provide a copy of the written agreement that created my original requirement to pay. 
If you are asking that I pay a debt that somebody else is or was required to pay, identify that person. Provide verification and documentation about why this is a debt that I am required to pay. 

The amount and age of the debt, including : A copy of all the billing statements sent to me by the original creditor. 
State the amount of the debt when you obtained it, and when that was. 
Provide an itemization, and detailed financial accounting, showing the dates and amount of each Interest, fee and charge that was added, from the last time the account had a XXXX balance, up to the final statement. In addition, explain how the added interest, fees or other charges are expressly authorized by the agreement creating the debt or are permitted by law. 
If there have been any payments or other reductions from the original creditor, from the last time the account had a XXXX balance, up to the final statement, provide an itemization showing the dates and amount of each of them. 
If there have been any other changes or adjustments from the original creditor, from the last time the account had a XXXX balance, up to the final statement, please provide full verification and documentation of the amount you are trying to collect. Explain how that amount was calculated. In addition, explain how the other changes or adjustments are expressly authorized by the agreement creating the debt or permitted by law. 

Tell me when the creditor claims this debt became due and when it became delinquent. 
Identify the date of the last payment made on this account. 
Have you decided that this debt is within the statute of limitations applicable to it? Tell me when you think the statute of limitations expires for this debt, and how you determined that. 
Details about your authority to collect this debt. 
Does your firm have a debt collection license from Illinois? If not, say why not. If so, provide the date of the license, the name on the license, the license number, and the name, address and telephone number of the state agency issuing the license. 
If you are contacting me from a place outside of Illinois, does your firm have a debt collection license from that place? If so, provide the date of the license, the name on the license, the license number, and the name, address, and telephone number of the state agency issuing the license. 
DO NOT contact me about this debt in any way other than what I have authorized below, or at any other place or time. It is inconvenient for me to be contacted except by writing a letter to my address above, as I authorize below. 
DO NOT call me or anyone else about me. DO NOT contact anyone about me in person, by writing, calling, using a computer or mobile device, on social media or in any other form or way of communication. 
Your only form of communication with me will be in writing letters to the above address by US mail. You will NEVER contact anyone else in any way, at any time, about me. 
Stop all other communication with me other than writing a letter to my address above and record that I dispute having any obligation for this debt. If you stop your collection of this debt, and forward or return it to another company, please indicate to them that it is disputed. If you report it to a credit bureau, also report that the debt is disputed.