The limitation period for making PPI claims is 6 years from the date that you could reasonably have discovered that you were the victim of mis selling - and you can claim all the way back to the beginning.
You are entitled at least to your money back and 8% - but you may be entitled to more.
The Ombudsman will award you a minimal award. You stand a chance of getting more money from the courts.
You will be suing for money paid under a mistake and you would be entitled to restitutionary damages.
Be aware that your lender is unhelpful and some companies like Lloyds have been acting positively dishonestly. In fact you shouldn't trust Lloyds about anything. They are deceitful and unscrupulous.