HI and welcome
I have claimed back for the last 6 years. Check over the FAQs on this site. Everything you need including some one to help you through it is here on the site (letters in library section)
As for Tesco, wait for the reply, theya re usually very good. However if you are not happy, write to the head office explaining exactly what has happened. Give as many details as you but be precise(no going off on tangent lol) Explain because of the messing around you have incurred the charges and include in your letter a copy of the charges from you bank (preferably on a bakn letter)
Hope this is useful, let me know
Sue
All advice is given through personal experiences, if in doubt seek legal advice