Blocked account

I opened an account at Relay on the 4 March 2023, I was informed I would pay a deposit on all purchases until the 1st of April when I make my first payment. I understood the terms. I then made my first purchase at Sportscene Kenilworth and paid a deposit, upon returning home I realized that the shoes I purchased had 2 different sizes in the box after the cashier "checked" the shoes at the till before ringing up which he obviously he didn't do. I then returned it to my nearest store and exchanged it and they again charged me another deposit on an exchange and they refused to reverse it. I was absolutely livid about that. How can I be charged twice for the same shoe. They told me it would be credited to my account. I did not purchase anything else on my account. I made a payment on my account the 31 March 2023. I decided to make an online purchase on 1 April 2023 but it was declined, only to find out my account is blocked. I didn't even use my account but it is blocked. I work, I make extra income and I am able to pay my account but it is blocked and I can't make any purchases. This is really terrible services. I am not happy I cannot use my account.