Ombudsman /HSBC Offer letter for PPI Claim!!

nicholas.t_2

I had a business back around 2002, I went to HSBC bank for a loan. I got a £10,000 business loan and a credit card with a £3,000 limit. I was told that to take out this loan and card I would need ppi. my business started to fail and I run up debts to around £18.000, I then tried to claim off the ppi for the loan and the card which were over there limit with some missed payments. I was then told that as I was self employed I could not claim even though I had paid for the ppi as part of the loan and the card.
I talked to the bank and they then arranged a managed loan for me to pay off the £18,000
this was at £280 per month. I was paying this off but had difficulties in doing so as my business had failed. A couple of years ago I fell into arrears with this managed loan and a new agreement was set up so that I only paid off the loan with no interest added this is now £115 per month.
not long after this was done I was told by a company that the bank had done this due to the fact the original terms and conditions were wrong and if I had talked to them before the rearranged managed loan was set up the original loan would have been annulled.
I am now still In debt to the tune of £13,000 plus, as I cant afford to pay more. IF I was able to claim off the ppi which I now consider I was missold I would have had the debt cleared.
I therefore think I should be compensated for all the anguish I have had over the last 8 plus years and the existing loan of £13,000 cleared. also all the payments I have made towards paying off this loan should be returned with the appropriate interest.
Due to all the above I have not been able to obtain any form of credit.
I contacted the bank about this and was sent a claim pack
they hold all the account numbers and all the payment details as they have told me this.
due to the length of time involved I do not have any original documents for all the above but have been told I can obtain the information from the bank at a cost ....
I today had an offer off HSBC
for £471.91

are they for real
any advice please