I think you dodged a bullet by getting your money back and getting a stihl.
amazon reviews are less than encouraging, its just a chinga piece of carp and would not be dependable.
I have one that is one of the early chinga clones like that, but was the higher end of the junk heap, it does the job, but the extension poles are thin walled, and easily bent, and once bent, are ruined.
The clips to hold the tubes in place bend and come undone, they have very basic bushes in the tubes, and I oiled them all, and went thru it, replaced the cheap fuel hoses, and grommet on the tank, for what it can do, every now and then, its ok for mr home owner on the weekend taking down that pesky 2" branch that overhangs the gutter.
The cutter head is just made of chinga plastic steel, and dont expect much from it, the other issue those things have, is the rubber oil hose from the tank to the bar pad, they perish in a very short time, and you cant get the parts/ hose to replace it = buying another cheaply made head, the covers for the bar are very weak plastic, and fall off regularly, even with the nut tight, and even when you put further washers and build it up, they just fall apart.
Get an echo, oleo mac, stihl, anything but those cheap clones, which will leave you stranded in the middle of a job when you really just need to get the job done.
I ended up getting a hedge trimmer attachement for it, and on an extension or two, is handy, but I dont depend on it, or expect it to be reliable, having said that, the power head has been surprisingly reliable after going over it and tidying up the poor assembly, it was a cheap garage sale find, so worth it just for that, but as said, not dependable on a job.