Other Fuel System Hoses Lines/piping, And Fittings problems of the 2016 Kia Motor Soul

Recently, I have been experiencing problems with my pumping gas into my car. Every time I attempt to put gas in, it overflows as if it is full, but it's not. The gas cap no longer clicks when attempting to close. I can only put in no more than $5 into my tank.

I have a 2016 kia Soul, fully loaded model. Six months after buying the car from the dealer (bought new with 8 miles), I began having problems with acceleration, from a stop or slow. The car would hesitate/lag/almost stall for 2-5 seconds, before catching and starting to speed up. I took it to the dealer. They couldn't find anything wrong with the car. I still have the car and I continue to have the same issues. I take the car in for regular oil changes and every time, have mentioned the acceleration problem and each time they say they can't find what's wrong with it. The last time I took it in, about 4 months ago, they said to put gas treatment in the tank and if I the problem persists, then bring it in to have the crankcase filter changed (this is the upsell they've been pushing on me for a year now. I have under 30,000 miles, most of which are cross-country miles. Today, I have the same acceleration problem but this time around, the check engine light comes on and the brake pedal was very spongy and difficult to slow, when breaking to pull over. I pulled over and put the car in park and let it idle to listen for any odd or unfamiliar noises. The car sounded normal. I scheduled an appointment with the dealer. This acceleration issue happens on the city streets, as well as the highway.