Unfortunately it could take some time.
I had a problem with Tiscali a couple of years ago & wanted to cancel an account.
Phoned them several times, wrote to them instructing them not to take any more money from my credit card.
That stopped them from taking any more money.
They owed me £48.00 which took them about 6 months to repay.
But they eventually did.
Their phone numbers are on their website.
Keep phoning & good luck.