Membership Application and Renewal page not proceeding to Contribution Webform

Dublin Food Coop is a member based consumer co-operative in Dublin. Our CiviCRM version number is actually 4.6.15 which is not available in the Version dropdown.
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Our web page to allow new members pay their subscription on line stopped working back in April 2016. Instead of proceeding to the page where a new member can enter their card details they get the following errors:

• Card Number field is required.
• Security Code field is required.
• Card Type field is required.
• Billing First Name field is required.
• Billing Last Name field is required.
• Street Address field is required.
• City field is required.
• Country field is required.
• Postal Code field is required.
• Credit card expiration date cannot be a past date.
  All these errors are being reported before getting the chance to enter any card details and the form to enter the details does not display.
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  Issue appears to be with this component on our Contribution webform:
  Contribution Page civicrm_1_contribution_1_co... CiviCRM Billing Fields Membership Application and Renewal
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  The Payment Processor is Stripe and Stripe confirms that no contact has been made by our contribution page since the process stopped working.
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  Any suggestions greatly appreciated.
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  Thanks,
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  Gaby and Tessa