Be carefull when buying or asking for service if you don't want to lose your money

When I bought my tent trailer from Traveland in Langley, I made an arrangement with the sales person that for the whole price that I will pay they will put in my SUV and in the trailer all the equipment necessary for a safe trip with my family as I didn’t know anything about what to buy and use, so they marked all equipment to be put including a stabilizer. When I went to pick up the trailer they were charging me $500 extra because according them, they installed a better stabilizer, which I didn’t authorize. After a long discussion they agreed to don’t charge me the extra money.
Two weeks ago one of the cables that raise the tent trailer broke and with a friend’s help we checked it out and isolate the broken cable, which just need to be replaced. Because it didn’t have a warranty as the trailer is used, I took it to be fixed to Traveland. Our agreement was that before start doing any repairs they will call me for me to authorize the job. So, I received the call charging me $500 for the repair, then I did not authorize the job, so they told me that to release the trailer I have to pay $150 for one hour of work. How can they spend one hour checking for a cable that was exposed and has to be replaced? I asked and they told me that they were trying to fix it.
I went there and complain with the Service Manager who didn’t believe me that they told me they were trying to fix it without my authorization.
At the end I had to pay $150 for nothing.
Please don’t buy or go for service with this company if you don’t want to lose your money.