@Garryh Hi there, let's take a look here. Tell me, when you upgraded the last modem how long was the contract you agreed to? Did you know that you can upgrade 3 months before the end of your contract?
@Garryh As your contract is due to expire in August you'll be able to contact us in May to discuss upgrading your modem. Upgrades can only be offered 3 months before the end of your contract, this is the same for phone upgrades and modem/router upgrades. As you have had your current modem for more than the 14 day return period for online or telephone orders it's not possible to return it at this stage. However, there are many tips and tricks on All about: Broadband Coverage which could help increase the 4G speeds you're receiving.