We work with an outstanding service provider who services Southeastern Pennsylvania. If you are in this geographic ares, I can send you their contact information.
Based on experience, I recommend in making your decision you consider the breadth and depth of a provider's technical support (in particular responsiveness), security (including availability of full encryption of all transmissions of email, data and storage), access to leading state-of-the-art technology, and cross-platform support (including computing, phone service, operating systems and hardware).
The cost of these services almost always is higher than one would guess, but that often is because the outstanding providers provide more value for what most people don't even know they need.
Consider documenting what services you will be providing to your clients over the next 2-3 months, and seeing if there is a way to deliver those services without compromising the integrity of clients' data, and be prepared to discuss with a successor provider strategies to get support through a transition period. In our business, we have an obligation to protect the information entrusted to us.