here is your answer NO they are poor customers services dont know anything and reception is diabolical
if you want good reception goto ofcom sitefinder it shows all the mobile masts in the uk , just enter your postcode and you can see all the masts in your area , they are indicated by a blue triangle , i guarentee 3 has no more than 1 mast in your area and others will have 6 or more. ofcom is a government site check it out to see what provider will have best reception