I bought a 2014 Jeep Grand Cherokee from US and shipped it to Africa. My u connect does not tune some of my favourite local FM stations. What would be the problem

No worries, I would not purchase one until you contact jeep about troubleshooting the system. If they are no help, and knowing the antenna might be the issue, you may want to replace it just to rule it out. But keep in mind, you may have an issue with the antenna amplifier, radio, or possible in the wiring harness. If the vehicle history report shows indications of water damage, as many have in the southeast USA right now, you may end up chasing through the wiring harness to find corrosion at a connection.