My Car ignition wont start up

when i put the key in and turn on the car the lights radio ect starts up but the
ignition wont start. if you jump start the car it will start after much difficulty.
Have checked battery its not the problem. I also dont see loose cables when
checking the engine.Petrol was on low reserve and i filled it but not much,my
car didnt start after that we had to jump start it to get home.
if you could kindly assist i would appreciate. C220 is the make