Please help the back of my new TCLC6US 55 is making a popping or tick sound guys at the store refuse to change it for me they say this issue normal

[mikeypony]

So the issue happens every 15 to 20 min The popping sound that the tv makes comes from Hdmi area or at the center of the back of the tv it sounds like something is bending the plastic so i decided to return the tv back to the store i bought it from the boss at the store got a technician in and he look at the tv then later he said there was no issue with the tv then the boss at the store called me in told me that noise tv was making is normal please anyone who owns a TCLC6US does this issue happen to you too