In which case, whatever is causing your issue, hasn't been reported yet.
Call 150 from a VM phone, or 0345 4541111 from any other phone, and follow the prompts for "I have a fault". An agent should be able to check things over and arrange the next step - possibly an engineer visit or replacement box. I don't advise accepting further reboots or "stronger signals" as a solution, which have been known.
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