Chosen Solution

I had my phone repaired at a local shop for a dodgy aux port. They replaced this part but I now have no signal whatsoever the carrier settings don’t even show and the battery died extremely fast. The back gets really hot and to top it off the aux port is fuzzy and crap. I went back and they replaced the part again turns out to be exactly the same. I got a refund but after looking into it it’s far cheaper and easier to fix myself. Before I start any tips or explainations to what my phone is doing? Much appreciated. iPhone 6s

Hi they just replaced the charger port bit. No idea what else was done to it. All i know is that i have no signal at all. Where can i buy genuine parts or parts that will work because i have a suspicion that the part that has been replaced was cheap and rubbish. Ben it displays the imei number and the modem firmware is : 2.30.00 Is that right?