Affiliate Marketing Secrets

Here is the story..
I was working for this nameless company for about 3 years I would say, I started working as data entry, just basically inputting information into a program. I held that temporary position for about 6 months, after that I was put into the company as a full time employee and joined a newly created Marketing Team.
I worked in that team for about a year and a half maybe? After that, I was doing half my time in marketing and the other half I was being trained as an estimator. Person who would receive the requests for material and then add the earnings, taxes freight and stuff like that.
Anyways, I was really fed up with that company I was promised raises for the longest time, I helped develop a lot of new strategies and implement new tactics, etc.. This year, 2012, I started fresh, first day I just quit, didn’t even call show up or give a two weeks notice, I figured it wasn’t fair for me to have to give a formal notice after I had been treated the way I was treated and have to train somebody else with all the stuff that took me vital time to learn.
Anyways, time after that, months probably around april or something, I can’t really remember, a friend of mine approaches me. Somebody who does the same thing as my ex employer. He asks me if I could send some requests for pricing to some distributors, it happened that one of the distributors I contacted via EMAIL, let my ex employer know. Actually forwarded the email, mind me..
In no way was I pretending to work with nameless company, actually they didn’t even know me, the way it happened was like this. I asked for material from them, the manufacturing company. The manufacturing company was lazy and contacted one of their distributors and asked them, “hey there is this guy near you who needs this material. Wana take care of him?” So that is how my ex employer found out that I had send an email to them.
Just for details, I never at any time signed any form of confidentiality agreement or anything by that sort. Just recently first days of june I received a letter, a Cease and Desist letter from some law firm claiming that I knew internal secrets from my ex employer and I was using that to harm their company by being in competition to them. In the form it claims that I am breaking something mentioned not by writing but by logic in the employee handbook (which is funny because we never had one, never ever. Actually the HR for the company was hired at the same time I was hired, a week prior to me.. Before that the company didn’t even have an HR and she was creating the handbook barely like a year ago, something that was never finished and I never received anything).
The letter gives me 30 days to respond or else legal action would be filed and I could be liable for expenses. My quesiton is this… Is that possible? Would they have enough grounds for anything like that to be held up in court? I mean I never signed anything, I guess you could say I did know internal information from the company, but it is stuff I never took from them nor did I ever use it against them. The company I contacted I found through google, it just turned out it was a manufacturer that provided my ex employee with products.
What would be my best step? I really need some advice guys. I have stopped contact with my friend who had the other company completely, stopped everything i was doing (which was only really asking for prices, no purchase was made, nor did I contact any clients what so ever) I do know that in Texas it is illegal to contact your ex employers CLIENTS, which was not done in this case, all I did was contact a MANUFACTURER for PRICING, that is it!
Thanks guys, I am in need of some serious guidance, I already dragged it out up to right now, I have around 10 days before the 30 days it said on the letter are completed.