new contract plan

Hello support team, yesterday i choose in the app new plan for extend my contract for two years, 20 euro per month with discounts. but today i got 42,99 euro,that’s not good,i really very disappointed with you, can you please check where are the problems, and correct it please , than i will continue with you , otherwise i have to switch my this phone number, because it is very high price, and you show something else in app and now doing something else, so look into this matter and solve it as soon as possible, thankyou