Unauthorised Refund close to 20 x the amount of the Initial Refund!

Worst service ever. I have been ****med by Paypal. I processed a refund request of £250GBP, they changed the amount to £4 763,41 GBP without contacting anyone. They say they have a policy of not giving back more than the initial refund amount, but this amount has been taken out of the seller's bank account and now they are saying the money has been paid back into my bank account, which it was not.

Whenever I call into Paypal, they tell they cant give me information on this.

I need answers!