Theur website issues are costing me money!

Leroy Merlin online shocked me this week! I initially put 6 poles in my cart on their online shop. I then added 1 more... making it a total of 7. I then proceeded to payment. The total was correct... R1000 something. When I entered my bank card details, the amount that got deducted from my card was R2400! It then stated that I ordered 13 poles. I immediately emailed them explaining that I only want 7 and that the money should be reimbursed or credited to my account.This was on Monday. I emailed every day from there onwards. I also called their call centre who didn't know who to put me through to and eventually got cut off. Today, a delivery company delivered 14 poles. I accepted 7 and sent 6 back. I wrote a note on the receipt explaining all of this again. I will NEVER EVER buy from them again!!! I was sent a survey this morning and completed it... you would think that someone would jump on this asap but still...nothing!