Fix 5080 error from SagePage on a custom Wordpress Plugin (PHPP

Recently we have been abandoned by our PHP developer, and it has left us in a pickle with a website that we needed to transfer to a new server. I managed to fix 3 of the issues caused by his shoddy code, I think a few of the issues were differences MYSQL versions with one server running 5.5.60-0ubuntu0.14.04.1 and the other 5.7.23-0ubuntu0.16.04.1 However, now sage pay is no longer working giving me a 5080 error. It worked fine on the old server, but not on this one. Unfortunately, the old server has been shut down now It looks like not all the data is being transferred over but I am unsure. The specific error is: 4001: The VendorTxCode has been used before. All VendorTxCodes should be unique. The request source: vpsprotocol=3.00 txtype=PAYMENT paymenttype=PAYMENT vendor=gledhillrespons vendorname= accounttype= username= website= vendordata=0 vendortxcode=0 amount=99.50 currency=GBP description=Gledhill Cover vspterminal= address= postcode= billingpostcode=FY2 9UR billingaddress= deliveryaddress= deliverypostcode=FY2 9UR contactnumber= contactfax= customeremail= basket= allowgiftaid=0 applyavscv2= billingsurname=Smythe billingfirstnames=James billingaddress1=1Antrim Road billingaddress2= billingcity=Blackpool billingcountry=GB billingstate= billingphone=xxxxxx deliverysurname=Smythe deliveryfirstnames=James deliveryaddress1=xxxxxx deliveryaddress2= deliverycity=Blackpool deliverycountry=GB deliverystate= deliveryphone= referrerid=2A5072CC-F0E2-4170-A6BB-0721C4F0759B billingagreement= token= storetoken= basketxml= customerxml= surchargexml= firecipientacctnumber= firecipientdob= firecipientpostcode= firecipientsurname= successurl=[login to view URL] failureurl=[login to view URL] vendoremail= emailmessage= crypt=