Could you use a little advice on recently delivered speakers..

Purchased a pair of standmount speakers, pre-owned, on eBay from a guy with 100% feedback (as I have as well). I asked him to please pack carefully, use lots of  Styrofoam and/or double box due to carriers being rough. He told me in the past he has UPS do the packing, he had no problem for previous amps he sold and if there is an issue UPS would be responsible. Speakers came. Packing was lousy, literally just a couple winds of thick bubble paper around each one, one speaker was face up with connections plugs facing bottom of box, no styrofoam peanuts nor cardboard nor anything else taking up space in the shipping box. Plugged them in, they seem to sound fine, however I noticed on one of the speakers (the one with plugs facing the bottom of box) the black connection wiggles a little bit, seem a touch loose, I’m guessing likely from contact with being bounced around. If I wiggle it a touch I get a static, but once I let go it sounds fine. The price was good due to being used and no grills, so far the speakers are sounding really good, and I’m please with my purchase, but I’m concerned if this is something serious or a future problem or something I can remedy without fuss. Your opinion on how to handle this issue?  https://photos.google.com/photo/AF1QipPGEYHT7sIiLOR6Fjnn9ExuoOT_ITLfJvBWjPUt         https://photos.google.com/photo/AF1QipMv5ytW0bvbUElXsconDMI2dmRw74xhdDt-I7xJ