Don't return it.
The battery symbol and the bars inside are the charge level indicator. The number on the display is the cell temperature (you should see either a "C" or an "F" beside it). The reason for that is because you don't want to charge the pack if that is showing triple digits since it is a Li-Ion pack. If you have just used the pack heavily, like the inverter at 90-100% for a while, and then come in to charge it, the pack will probably be over 100 degrees Fahrenheit, and you will want to let it cool a bit before charging. If the cells are over 160 (and it may not show that high) even a smaller charge current could push it to thermal runaway where the charge current adds to the temperature and pushes it more and more till the cells go boom. Not sure how high the display will actually show, but if it starts to go past 120F when using the battery, or 100F when charging, keep a watch on it. If it continues to climb, STOP either using it, or charging it. 86-89F is fine while charging or discharging, 86-89C is very dangerous.