My iphone 7plus won't charge? I can't tell if it is phone for the reason why it won't charge or the phone chargers i have are bad?

I have an iphone 7 plus. It was all fine until battery went dead on me and went to grab my charger to charge it. Doesn't work. I tried two other ones I have doesn't even recognize them. It acts like nothing is connected showing the cable with lightning bolt. If it was charging it would just show battery symbol. I tried connecting to the computer and still nothing. I'm hoping it isn't the phone and just the usb cables are bad? I've even tried a hard reset, but no that doens't work either it is too dead to do anything. It is acting as if any cable I have it won't pick it up. Could it be a compatibility issue? It said iphone 7 on the box chargers came in so I thought that would me compatible. I'm losing my mind having no phone for work! Hoping someone can help.

This happened to me once. Try putting a toothpick in the charging port and pick out any lint that is in there. Don't use anything metal. Hope this works for you too.

It's crashed…

It happens quite often with phones and tablets if the battery runs down completely.
They try to continue when power is reconnected but the content of the RAM has gone and the CPU is reading garbage instructions. It does not know what to do or what device it is in.

Once it has been on charge for at least two hours and with the cable still connected, press both the power + volume-down buttons together for about ten seconds, until the Apple logo appears.

That's a hard reset, the same as pressing "reset" on a PC.
It forces a proper reboot, with the phone starting up normally as if it had previously been turned off.

It does not delete anything.
(Occasionally, you may have to try it more than once if the phone does not start up properly within a few minutes of the first try).

For older iphones / ipads, the equivalent reset is power + home at the same time, for most android devices power + volume-up.

If you do it too soon after connecting the charger, it often will not work. It should at least switch to the low battery symbol if the reset works, but it may not actually turn on normally until the battery reaches at least 20%.

Fast charging is controlled by software & the battery may only be getting a minimal trickle charge until the CPU kicks in to take over, so the pre-charge time just to get enough into the battery for it to be able to run can be rather long, not like when it's working properly.
Prior to that, it may take eg. An hour to give the equivalent of a minutes normal charge. Trying too soon just runs it down again.