Phone number change

Hi guys ive changed over to lebara and I wanted to keep my old number. I got the code and everything and they messaged me to tell me my phone no had changed to my old one. But when I phone people its the new number on the SIM that arrives that shows up ??? Can anyone shed light on how to fix this problem.

Have a look in your phone operating system and make sure the number your retaining is in the correct places,remove the number Lebara gave you on the sim. If still the same is happening when you’re tried to be contacted ask for portin to be done again. All the best

Thanks will give it a try 😀