Can anyone assist please?  We are using Sage 50 VAT Cash Accounting Scheme.  We have received two final invoices from our telephone provider with vatable and non vatable amounts on them, and I have posted them to our purchase ledger.  However, when I try to post the payment it will not allow it and shows the error message 'there is a mismatch in the net/tax elements of the payments selected'. 

I then amended the postings in transactions so that all entries were showing the T1 code but leaving the vat amounts the same, this still did not allow the payment to be posted. 

Has anyone encountered this and if so how did you overcome it, please?