In order to get that far (displaying correct characters) things have to be pretty close.
There isn't much to go on, but 99% of the issues are related to wiring, or connections.
Most are incorrect wiring, but it can also be poor solder joints, broken wires,wires not making proper connection, or in some cases a display that needs a different configuration for its chip select pins.
If I were to guess, I'd suspect the chip select connections, but that is just a guess based on little input.
The best thing to run is the diagnostic sketch to test out the h/w.
It displays information on the display and on the serial port.
You can see the expected output in the documentation.
The information from the sketch can help narrow down the issue.
Run that sketch and report back what you see on the display, and post the serial output from the sketch.
--- bill