State the Consumer Rights Act and get a full refund.
You are entitled to a full refund under the law, so don't get fobbed off by Go.
Sorry Cairncamper that's not true -
"This right is limited to 30 days from the date you buy your product. After 30 days you will not be legally entitled to a full refund if your item develops a fault, although some sellers may offer you an extended refund period. "
"If you discover the fault within the first six months from purchase, it is presumed to have been there since the time of purchase - unless the retailer can prove otherwise."
"After the first six months the burden is on you to prove that the product was faulty at the time of delivery. "
"If you are outside the 30-day right to reject, you have to give the retailer one opportunity to repair or replace any goods or digital content which are of unsatisfactory quality, unfit for purpose or not as described. You can ask the retailer to repair or replace faulty goods but it can normally choose whichever would be cheapest or easier for it to do.
If the attempt at a repair or replacement is unsuccessful, you can then claim a refund or a price reduction if you wish to keep the product.
You're entitled to a full or partial refund instead of a repair or replacement if any of the following are true:
the cost of the repair or replacement is disproportionate to the value of the goods or digital contenta repair or replacement is impossiblea repair or replacement would cause you significant inconveniencethe repair would take an unreasonably long amount of timeIf a repair or replacement is not possible, or the attempt at repair fails, or the first replacement also turns out to be defective, you have a further right to receive a refund of up to 100% of the price you paid or to reject the goods for a full refund.
If you don't want a refund and still want your product repaired or replaced, you have the right to request the retailer makes further attempts at a repair or replacement."
The Consumer rights act can be found
HereAs previously suggested, take the item back to GO and see what they offer.