Why does my user input only get accepted the second time?

I'm having problems with my first input loop. I'm trying to use them to validate input, but I have a problem where entering correct data on the first try still receives an error. Entering that same data a second time will result in true. This happens in my first loop but not my second.

// previous cin ^
// contribution input, checks for numbers only
    cout << "Please enter their contribution amount: ";
    cin.ignore();
    cin >> total[i].contAmount;    // total[i] is a vector of structures
    while (!((total[i].contAmount >= 500) && (total[i].contAmount <= 20000)))
    {
        cout << "Please enter a valid number between 500 and 20000, for example: 14382.53. Only use numerals or periods: ";
        cin.clear();
        cin >> total[i].contAmount;
    }
// telephone number input, checks for 10 numbers
    cout << "Please enter their telephone number in this format: 1234567890: ";
    cin.ignore();
    string tempNum;
    getline(cin, tempNum);
    while (!((checkPhone(tempNum, 10)) && (tempNum.length() == 10))) // checkPhone function uses isdigit to check for only numbers
    {
        cout << "Please enter exactly 10 numbers (ex 1234567890): ";
        cin.ignore();
        cin >> tempNum;
    }
    total[i].teleNum = tempNum;

It probably has something to do with cin >> vs. getline, but I don't know how to use getline with my vector/structure. I know I am also probably using cin.ignore() improperly, but when I don't use it my code jumps to the next cin without letting the user input anything.

Thanks for your help.