Japt -¡, 15 bytes

pÊv è`%ßé[^Ãäu]

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pÊv è`...     :Implicit input of string
p             :Append
 Ê            :  Its length
  v           :Lowercase
    è         :Count the occurrences of
     `...     :  Compressed string "%bill[^ayiou]"=/\bill[^ayiou]/g
              :Implicit output of result as a boolean (0 is falsey)

Japt -¡, 13 bytes

Takes input in lowercase

pÊè`%ßé[^Ãäu]

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pÊè`...     :Implicit input of string
p           :Append
 Ê          :  Its length
  è         :Count the occurrences of
   `...     :  Compressed string "%bill[^ayiou]"=/\bill[^ayiou]/g
            :Implicit output of result as a boolean (0 is falsey)

Japt -¡, 15 bytes

pÔv è`%ßé[^Ãäu]

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pÔv è`...     :Implicit input of string
p             :Append
 Ô            :  Its reverse
  v           :Lowercase
    è         :Count the occurrences of
     `...     :  Compressed string "%bill[^ayiou]"=/\bill[^ayiou]/g
              :Implicit output of result as a boolean (0 is falsey)

Japt -¡, 15 bytes

pÊv è`%ßé[^Ãäu]

Try it

pÊv è`...     :Implicit input of string
p             :Append
 Ê            :  Its length
  v           :Lowercase
    è         :Count the occurrences of
     `...     :  Compressed string "%bill[^ayiou]"=/\bill[^ayiou]/g
              :Implicit output of result as a boolean (0 is falsey)

Japt -¡, 14 bytes

pÔv è`%ßé[^à]

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Japt -¡, 15 bytes

pÔv è`%ßé[^Ãäu]

Try it

pÔv è`...     :Implicit input of string
p             :Append
 Ô            :  Its reverse
  v           :Lowercase
    è         :Count the occurrences of
     `...     :  Compressed string "%bill[^ayiou]"=/\bill[^ayiou]/g
              :Implicit output of result as a boolean (0 is falsey)