Tax Invoice

Need a Tax Invoice for work claims. Every single month I have to call multiple times because they first send a statement instead of a Tax Invoice, then when I call to get this corrected I get a regular invoice, not a Tax Invoice. Now when I try call for th e latest one I get an automated voice message telling me I can't call the centre as I've exceeded the number of calls I'm allowed.

First restricting the number of times your client can contact you, in regards to a service that they are PAYING you for is backwards. Second if the call centre was able to action a simple request then I wouldn't have to call them multiple times every month.