I recently went travelling and unlocked a Samsung galaxy Rugby through Telus. I traveled for 6 months and used the phone in many countries with many different sims, successfully. Once back in Canada I tried to put my koodo sim in, but when I have my koodo sim in my phone, it switches between service and no service. 30 seconds of service then 30 seconds of no service. I called Koodo and we went through a bunch of settings and they tried some things on their end, but after a few days nothing was working. they told me to do a factory reset on my phone so I did. still no luck. The sim works fine since its in my old phone right now. I just can't figure out what the problem is? Any suggestions?