Bought a 105 4G .
First time used only recognised 1 SIM slot.
few weeks later the other one packed up.
It was a cheapo new purchase from a bucket phone shop.
Dont think itd be easy to get refund.
the slots are far too finniky you need a jewellers loup just to decipher the directional diagram size of pinhead and a sharp butter knife to get the SIM out.
A previous 3 G one I bought the hatches broke off at first use.
As for how you increase volume without being in the middle of a call looks like you...cant