Are these on SD or HD channels? Which Sky Sports channels?
Pixellated pictures on live TV are often the sign of a signal fault. If you've rebooted your box once, then there's likely a fault somewhere, so call VM and report it. You're likely to need either an engineer visit or a replacement box, depending on what VM's remote diagnostics turn up. They can do these while you're on the phone to them.
First check the automated faults line for any existing issues in your area that could be the cause: 0800 5610061. If nothing's reported, assume VM don't know about your fault and you'll need to call them.
150 from a VM phone, 0345 4541111 from any other phone - choose the options for "I have a fault with my TV service"
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