Can 3 lock my phone if i unblock it to use another

i want to buy a threepay phone because with the sim card you get a latest modle phone for only £50. Thought i could just unlock the phone and use my current sim, instead of HAVING to top up £15 a month like yo do with threepay. But, someone told me that if im not using THEIR sim, 3 can lock my phone, and it would be useless. Is that true? even if another sim card is in? is there any way i can stop this?

I had a nokia 7600 on three and had it manually unlocked. I don't know whether it was just me that experienced this but whenever i put a different sim card in the phone after 5 minutes it comes up "Please insert sim card". You could still use all of the features although there was a sim card but I couldn't make calls or texts.

The unblocking service I used was a clip and not just a code.

I wouldn't advise anyone to buy a 3 fone, i couldn't get a signal anywhere.

From Devon, UK,

My contract is about to end with 3 and I also have a Nokia 7600. I've unblocked it myself and tried it with Orange and O2 SIM cards and have had nothing weird happen.



I wanted it unblocked as my contract terminates at the end of the month.

From Wales,

Does anyone know if you can use an o2 sim in a 3 locked phone? Apparently you can....?