A company accused me of being in violation of US Trademark law?

Yesterday I got a certified letter from a company Id never heard of before.  Upon opening the letter I read how the president of this company owns the trademark rights for a saying I have been using on my website and listings.

She explained who she was and why she was writing and it simply said:

 'It is a violation of US trademark law to use a similar or identical mark on similar goods.  I appreciate your cooperation in this matter.'

Ok so normally I would freak out when these things happen but I didnt.  I didnt create these products I only sell them and used the same phrases that the vendor had provided me as a description of their products, how could I be a fault? Maybe I could plead ignorance?

So I called this company and spoke with the president.  She knew exactly who I was since she sent the letter.  I simply asked what is expected of me since I do not have knowledge of this and am unsure what she was expecting me to do.

She started to explain how it works. She said that since she owns that particular wording I am not allowed to use it at all. Especially since its in the same category. She also said that if I purchased the items from an international vendor I am responsible for correcting or changing the listings.  Turns out the company I purchased these items from were right here in the US and their products were made in the USA so no international issues here. So now I am in the clear!  I gave her the vendors information and she said I dont have to do anything for now, its between them and the vendor I purchased from and they have to tell me what to do depending on the outcome.

So be careful of violating trademark law.

I had a listing pulled from my eBay store accusing me of the same thing. The accused me of violating trademark by the owner. I said these are authentic and I have the invoice to prove as I purchased them from the owner!   eBay said I needed something in writing. I contacted my sales rep who contacted the owner and they apologized about the error.  But they didnt want their products sold on eBay. No one told me that! They were supposed to inform eBay of their error. Its been a few months and the violation has not been lifted from my account.  Guess I can pursue it more but its not worth it. The violations 'fall off' within a a few months so as long as I am 'good' Im fine.  I try to remember to ask vendors about this rule. Many vendors are starting to write it on their purchase orders and catalogs.  Ive seen notes about how their products are not allowed to be sold on eBay or on Amazon. How do they stop people?  They take down listings.  Funny thing is I can find many more listings from others selling the same product.  Why did they pick my listings? I kinda think they knew I was a vendor and instead of 'telling me' they punish me using Vero on eBay. Kinda messed up.