Sent my partner to pay my account, knowing very well that I'm owing 310 but she was told I'm outstanding 730

Sent my partner to pay my account, knowing very well that I'm owing 310 but she was told I'm outstanding 730. Of which she paid.. Now they owing me 420 and I have to go to the store to get refunded... Very inconviniencing and expensive for me as there are no Mr price stores near by ?