re-locked iphone4

16gb iphone 4 in UK. Software was up to date. Phone was given to me..unlocked from original carrier Swisscom in Jan.2014 as contract had expired. Used in UK with TalkTalk sim. worked fine. No issues for a year. Recently started getting "no service" messages. Then phone would work..then "no service" again etc. It would flip in and out of service sometimes overnight i.e. no-one was using/touching it.

Eventually I responded to a "restore via itunes" message..did a back up..restored..seemed to all go fine but at end it says "There is a problem with your phone"..take it to Apple store etc. Phone itself is on hello, hola etc..choose English..then input UK from list..then it says "connect to iTunes". Did that & then "there is a problem with your phone" etc etc. So I am going round in circles.

Before going to the Apple shop..some distance away..I spoke to Apple support (it was in Lisbon). I gave the IMEI & they said the phone's Activation Policy is linked to Swisscom "current and next". You need to talk to them. I then rang the Apple stor & gave IMEI again when asked..they said yes that is what we see too..you need to get Swisscom to unlock it again..as it seems doing the restore has caused it to relock to Swisscom for some reason and only Swisscom can unlock it..no point in taking it to Apple store... as Apple don't lock the phones the original carriers do.

So did an Online chat with Swisscom.."only you can do that"(unlock) they said..and gave me a link (https://www.swisscom.ch/en/residential/help/loesung/removing-sim-lock.html)..baiscally takes me to doing a restore as far as I can see..which won't work... it'll just be a repeat of what I have already done a dozen times with no difference in outcome. To summarise Apple are saying only Swisscom can unlock the re-lock post restore. Swisscom are saying DIY.. we don't lock phones anymore..but the instructions get me nowhere. HELP! Thanks for reading.