Card payment providers

[irishbloke]

Hi Guys

I was wondering if anyone had a current recommendation for a card payment solution, I know the best options may change since previous posts.

We are business to business sales only and looking a solution to take payments over the phone or to send a payment request to customers.
Primarily for smaller sums, a few a month in the 100-1000 range although there may be a few in the 2-5k range monthly.

Needs to accept american express as well

many thanks

[irishbloke]

I won't be taking any payments face to face, forgot to add