2012 Vauxhall Antara gearbox is needing replaced ! spent £1500 so far is it worth getting it done car in lovely condition dont want to get rid 2013 plate

When stopped at traffic lights auto gears would not select. Waited and turned off engine wen it cooled down it drove but only in first. Took to garage told needed sensors cost £1500 ?didn't fix problem told a flush could help another £120. Collected car drives slightly better in that it goes up into 3rd gear but again once it heats up it will stay in first. Told needs new gearbox ! Should I try reconditioned or scrap dealers or cut my losses. Since this happened saw many Antaras have same problem does vauxhall not have a duty to recall these as most have no where near the normal number of miles mine has only 71000 and I have only put 10000 on in 3 years !