Unfortunately, this isn't the first case of this we've heard. The DVLA is working through a huge backlog of applications as lockdown eases, but until they get to yours then it won't be returned. If you sent it months or weeks ago, it's far likelier to come back soon than if you sent it a few days ago - however, I'd try ringing and emailing (although, I'm sure you've already done this). DVLA told us the contact centre is dealing with everyone, not just essential workers anymore. But there will likely still be long delays.