Pending transaction disappeared (Halifax)

Good morning, first post and couldn't find what I was looking for so trying my luck here!

I attempted to purchase a Plusnet broadband and phone deal online, twice, and once via telephone only to be declined at the direct debit setup stage. Upon further investigation, it turns out the previous tenants of the home I've just moved into have put a cease on the line, and I cannot setup a direct debit until the 1st of September. I was told by Plusnet that the three payments they took from my account (from my card, one stage before the direct debit stage) would bounce back to me as the money couldn't go into a non-existing account.

The three attempted payments showed in Halifax's 'pending transactions' for 4 days, and now one has disappeared - it's not showing as being credited back to my account, and it seems as if the payment has been taken yet it's not showing in my recent transactions.

Can anyone shed some light here? Or is it simply a phone call to Halifax needed?

Many thanks!