Pixellation on live TV is generally indicative of a signal fault. OnDemand doesn't use the TV signals, that could be a different issue, possibly a failing internal modem on your TiVo. If recordings are affected, you could have hard drive problems.
All things taken - you are best to report your issues. Realistically, you have 2 options at the moment.
1: Call upto faults, speak to an agent and they should arrange an engineer visit at the very least. You allude to problems with this - what's the issue?
2: Wait on here for VM staff to respond, this may be less painful than calling but won't be immediate. Given that it's Saturday, you may be waiting a couple of days.
Depending how long you've had your current package, and assuming you have VM broadband, you could do worse than consider a swap from a TiVo to a V6. Same software, but much newer box that's far more capable.
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