Refund of premium after settlement of personal loan

I requested a settlement letter on my personal loan account, which was eventually received, it was settled on the 22nd of June however on the 26 of June my premium still went off, I have been trying to get them to refund the premium and close the loan account, promises between 5-7 working days, to date still no refund received and the account is still open. No replies to my emails and it proved almost impossible to get hold of someone to assist via telephone without holding on for at least 20 minutes. Not impressed with the service after banking with them for many years.