Sony Experia z and 3 mobile

I took out a 2 year contract with 3 mobile for sony xperia z mobile at the end of last august. There have been a few problems with the charging of the phone. On Christmas Eve I removed the charging lead from the phone and the spade connector inside the charging port fell out. We took the phone back to the 3 shop and we were told that 3 do not deal with sony and we had to contact them under the years manufacturers warrantee. We contacted Sony and sent the phone off to them for repair. When we talked to the rep from sony on the phone we were told that if they could not repair the phone it would be replaced.

We contacted sony today and were told the phone has been sent back to us as beyond economical repair. We asked if it was being replaced and were told it wasn’t and if we wanted we could refer it higher in sony.

As we took the contract out with 3 I would have assumed that they were responcible for the phones replacement, any advice

We have been back into the shop and were told that it only applies to the first 28 days after we took the contract out. they told us to go and look and the consumer rights act. We had showed them an example of a simmelar case where the phone had been taken out on a 18 month contract and had broken within 6 months. we were told by the person in the 3 shop that it was an old article as they dont do 18 month contracts anymore and they dident have to replace the phone.

Have you any info we can give them so they can see they have a legal responcibility to replace the faulty phone.