bank allows my account to go overdrawn

had to sign and fill in 5 separate chargeback forms due to my bank allowing this same company to take out 4 separate transactions one 4 £75.00 and 3 more sep transactions of £100.00 each witout my knowledge or my constent my cash card account £374.06 overdrawn as only had 94p in credit. where also the bank states you can not go overdrawn with a cash card account as well as with my visa debit barclay card can only uses as long as you have the money in your account . so i have had to pay back the overdraft the next day as my 2 special needs sons dla benefit paid into my account . also letter telling me they r not charging me 4 going overdrawn as said i was good 4 this
have sent back all forms recorded delivery 2day 4 full refund £375.00 a.s.a.p
how long will it be and will i get the full refund