Straight Talk 4G hotspot device reset button - where?? how??

Trying to reach a customer service representative at straight talk that can help me is proving impossible, so i thought I'd ask here, assuming you may have the same device -- the ZTE 4G Z289L LTE (currently straight talk's only 4G mi-fi device offered) -- and have also needed to reset it.

The problem is threefold:

1. The customer service representative says I need to push the device's reset button under the battery cover... but nothing under there is labeled at all.
   
2. Two things LOOK like a possible reset button (see attached image), but pressing either with a paperclip has not yet accomplished anything. Either I'm not pushing the right thing, or I'm not pushing it hard enough (don't wanna break it), or I've been given erroneous instructions by the rep. When I press the right button, does it "react" such as click or press inward? because I'm not feeling any physical indication that anything has been pushed.
   
3. Have I even been given the right instructions on what to do?? The customer service representative said to press and hold the reset button while at the same time pressing the power button on the front of the device, but if I'm indeed pressing the right thing, it isn't resetting. And because my finger is pressing the power button, as instructed, the device does shutdown, but doesn't do the promised restart/reset.

If you know what the heck I'm supposed to be pressing as the reset button, please do tell. I've marked the attachment wth (A) and (B) -- what I *think* might be a reset button. Is it A or B or neither? Thanks....

 

the link to the image: https://www.dropbox.com/home/Public?preview=open+back+device+with+arrows.png

 

i tried the battery removal thing, but it made no difference, nor did using the local device web page to soft-reboot it. The rep says it needs a hard (physical reboot). Thanks though.