Product: Checking or savings account

On XX/XX/20, while at work, my cellphone ( XXXX XXXX line ) service completely stopped working around XXXX. This has never happened before so I thought nothing serious of it. I turned off my phone for a little while and turned it on again and same was still the case. I took my simcard out and put it back in a couple times and still same problem. I used my work phone to call my phone service company around XXXX and while on the phone with them, they told me my phone number had been transferred to another simcard which was why I didnt have network on my phone. I explained to the XXXX XXXX   representative I only have one simcard and I didnt make any switch. 
I requested she transferred my phone number back to me which she tried doing thrice. On each try, the phone number would only transfer for a few seconds and automatically transfer back to the other sim. On the third try, she was able to transfer my phone number back. Immediately it transferred back, I started getting notifications in my email from XXXX XXXX that says '' my email address has been unlinked from my account and that my XXXX XXXX pin was changed ''. I checked my XXXX XXXX, I saw numerous transactions were made on my account which all involved money being transferred to different people from my account. Both my Santander bank account and my debit card were linked to my XXXX XXXX. Upon checking my bank account, all the money had gone with only XXXX cents left. The sum of {$4800.00} was emptied from my account. Immediately. 
I went to my bank ( Santander ) to file a fraud claim and they started their investigation. I tried contacting XXXX XXXX the same day and on XX/XX/XXXX, someone named XXXX from XXXX XXXX support emailed me asking for details concerning this issue. I provided full details and he said they would investigate and get back to me. On Tuesday XX/XX/XXXX, the same XXXX emailed me again asking for some more details which I provided. Around XXXX that same day, XXXX got back to me on email and basically said " there was nothing they could do about the situation since the transactions were already completed. He said XXXX XXXX " is unable to cancel or refund completed payments ''. He suggested I check with my bank. 
Meanwhile, my bank got back to me today and said " there is nothing they can do about the situation as at today XX/XX/20. XXXX XXXX said I needed to resolve the issue with the recipient. I dont even know who the recipients are. I was scammed. As of this morning XX/XX/20, I have emailed XXXX and let him and XXXX XXXX know I will be taking this matter up to XXXX XXXX XXXX ( XXXX ). Within 3 hours, multiple money was sent from my XXXX XXXX to different XXXX  XXXX  accounts within minutes of each other totaling almost {$5000.00} and XXXX XXXX is telling me there is nothing they can do about it, same with my bank. thats my whole life there. Immediately it happened, I had to call all my auto payment billing companies to stop/ postpone payments on my account. I currently have XXXX dollars in my name and practically live off my fianc. I only need XXXX to refund me of my money. I ask for nothing else than me to be refunded of how much was scammed of me through XXXX. 
I have lodged a new complaint with my bank ( Santander Bank ) and they promised to re-investigate my claim again and I pray this time they do a better job as these funds must have gone into an account with a bank, there should be an avenue for banks to interact when situations like this arise. I would really appreciate it if you could help me look into this and see that I get justice. Thanking you in anticipation.