Ll of a sudden the battery light comes on then I shut the car off

So I take my absolutely well maintained Lincoln. Fyi, only went over the oil change one time. All interstate miles. Everything perfect in that car until one day the air suspension goes out. Not shocking lol. Anyhow I get it back from the shop now it's acting like the alternator or serpentine belt or computer system is fried. It was absolutely fine the day I took it in. I get it out of the shop and all of a sudden the battery light comes on then I shut the car off go in the house. Next evening I head to work. No light. Okay fine. Well I get off work which is right before sun up and the headlights seem a little dim but still no battery light. Then I get to house go to sleep I just wake up head to grocery store before this hurricane. Heading home my lights go off my ABS goes out my power steering goes out and everything including my headlights start flashing. Nothing in my computerized dash is working. Engine still running thank God I only had about 2 blocks left to go home. I get home can't roll up my windows. Shut the car off try to turn back on battery just clicks. Let it sit for about 10 minutes I turn it back over the headlights start flashing but I have enough juice to roll up windows. Headlights still flashing on and off and on and off I open my back door to get the groceries they shut off.