<?php
mb_internal_encoding("utf-8");
$regexp = "/^(\\+7|8)[0-9]{10}$/ui";
$allNumbers = [
        $correctNumbers = [    '84951234567',  '+74951234567', '8-495-1-234-567',
    ' 8 (8122) 56-56-56', '8-911-1234567', '8 (911) 12 345 67',
    '8-911 12 345 67', '8 (911) - 123 - 45 - 67', '+ 7 999 123 4567',
    '8 ( 999 ) 1234567', '8 999 123 4567' ],
        $incorrectNumbers = [   '02', '84951234567 позвать люсю', '849512345', '849512345678',
            '8 (409) 123-123-123', '7900123467', '5005005001', '8888-8888-88',
            '84951a234567', '8495123456a',
            '+1 234 5678901', /* неверный код страны */
            '+8 234 5678901', /* либо 8 либо +7 */
            '7 234 5678901' /* нет + */]
];
$matches = [];
foreach ($allNumbers as $numbers) {
    foreach ($numbers as $number) {
        $correctText = str_replace(" ", "", $number);
        $correctText = str_replace("-", "", $correctText);
        $correctText = str_replace("(", "", $correctText);
        $correctText = str_replace(")", "", $correctText);
        if (preg_match($regexp, $correctText, $matches)) {
            echo "Правильный номер: {$matches[0]}<br/>";
        } else {
            echo "Ошибка! Введите номер формата: +7/8xxxxxxxxxx<br/>";
        }
    }
}
    ?>