WOW! Only took two posts before someone tried to up-sell you to one of the vastly more expensive units on the market - impressive indeed! I would suspect that something happened to knock the release lever out of Lock Tow mode. Check it all out, have a wrench monkey that you trust check it out and if you are satisfied that all is well carry on with what you have. Otherwise be prepared to grease up the billfold, put a couple of Viagra tabs into it and buy into the hype of the latest technology on the market.
Cheers!
Mike