<human>: Give me a shortened version of the text

About one month ago, I had a contractor come out and estimate the cost to repair my garage door.

Nothing was signed or agreed upon and there was no mention of this service costing. The tech came out, surveyed the repair requirements, and said they'd be in touch.

Soon after, they sent an estimate for repair. It was 2x the cost that was quoted over the phone (before the tech visited), and I sent back a message asking for clarification of the parts/labor, and why it was 2x the price (I know these things happen, I just wanted an explanation). Never heard back.

That is, until a few days ago. I received a mailed invoice for $50 for the "labor", to be credited if I go ahead with the quoted repair job (which, again, I asked for clarification/more detail on and was ignored).

My feeling is I don't owe this. I was never informed that an estimate would cost, nor did I agree to any such work for payment exchange either verbally or in written form.

The contractor has no information about free (or paid) estimates on their website. Again, at no time was I informed this could or would cost me anything, and free estimates are very common in home repair in general in my area, so absent that info, a safe assumption is that estimate are indeed free in most cases unless otherwise discussed.

What is the best course of action here?

I was thinking of either letting it go 30 days and see if they send a "30 day past due" notice or give up, or being proactive and sending a certified mail response back essentially outlining the above, that I wasn't informed of nor did I agree to any exchange of money for labor.

Thanks for any advice.
<bot>: Contractor charging for estimate without my knowledge/consent, unless I hire them to do the repair -- am I obligated to pay?